2017 Alex Hwang

Alex Hwang
Home University: Rice University
Field of Study: Electrical Engineering and Minor in Physics
Current Status: Sophomore
Expected Graduation Date: May 2019
Host Lab in Japan: Kyoto University – Institute of Advanced Energy, Matsuda Laboratory

Why Nakatani RIES?

Nakatani RIES has been my dream program for this summer because of the way it perfectly merges a rich study abroad experience and a serious research experience in nanoscale science. This internship presents the amazing opportunity to explore Japan, an exciting, innovative country rich in culture and tradition. I’m excited to go to Japan and compare what I see to my own Asian cultural heritage and experience. In addition, this program perfectly aligns with my career goals and research interests: I want to pursue a career in research in nanoscale science and engineering, especially with interesting, novel nanomaterials. As my mentor from Rice, Professor Naik, has told me, there is no better place to study materials than Japan. I’m so excited to be part of a program that creates a uniquely holistic, immersive research experience that will train me to become a more mature researcher. The research of the future will be of global scale, crossing many cultural bounds, and I’m so eager to become immersed in it this summer.

Goals for the Summer

  • Work as hard as I possibly can in the lab, keeping in mind that 9 weeks of research will fly by
  • Practice zazen (Zen Buddhist seated meditation) daily and visit a Zen Buddhist temple
  • Hike Mt. Fuji
  • Make meaningful and lasting friendships with other Nakatani fellows and colleagues in my host lab.

Excerpts from Alex’s Weekly Reports

Week 01: Arrival in Japan

3 owls away from home: Savannah, Jakob, and I posing by an owl statue near the Sanuki Club. We’re representing Rice (whose mascot is the owl) in this program! ~ Alex Hwang

Initial impressions
It’s difficult to capture the extent to which I have already fallen in love with Tokyo and Japan. Tokyo is a city bursting with excitement, with so many novel things to explore and discover. The public transportation system here makes quick travel a breeze, and basic Japanese proficiency can take you a long way in terms of communication ability. At the same time, Tokyo clearly has deep traditional roots dating back to its inception in the feudal days of Japan.

Before we traveled to Japan, our group had discussed at great length about cultural differences we might experience once we travelled. Even with this, and even though I have an Asian heritage and have traveled to several other Asian countries, I was very surprised by many of the things I noticed once I came to Japan.

Dressed up as a raccoon for Karaoke: Karaoke in Shibuya was one of the most fun experiences I’ve had in Tokyo. It is a must-do while here in Japan. ~ Alex Hwang

The first obvious thing to notice is the cleanliness, order, and timeliness of this city. It’s incredible that a metropolitan area of this size and industrial capacity is so ridiculously clean. There are no public trash cans (but litter is nowhere to be found); subway trains are never late; and people are always on time to appointments. Every small detail of Tokyo feels like it was planned out for some purpose.

Another thing that I’ve noticed is the kindness of the people here. Professors, teachers, university students, convenience store workers, hotel staff, store owners — you name it — have all been so incredibly welcoming to the Nakatani students and me. I didn’t really believe it when I heard it before coming to Japan, but it is true — people will go out of their way to walk you to a destination if you ask for directions and they will call you to return your wallet if you leave it on a subway train.

“Working out” at the Edo-Tokyo Museum: We had an incredible volunteer tour guide at the Edo-Tokyo Museum who was so helpful in informing us about the cultural history of Japan and Tokyo. She was pretty impressed with my technique in lifting this! ~ Alex Hwang

First activities
Our first week of introduction to Japanese society and culture has been a whirlwind of activity. We had an excellent introduction to the topic from our very own leader within Japan, Ogawa-san. It was extremely meaningful to be introduced to the cultural elements of this society from someone who has spent his entire life in Japan, but who also has worked in many global environments in several different countries. He introduced us to the idea that the Japanese seem to value relationships more than Americans, especially because their grade-school friends may well be their friends for life, and it’s common for people to work only one job after graduation.

On the other hand, we received a fantastic cultural introduction to Japan from Mr. Cain Gibbs, an American who has been living in Japan for the past 9 years to teach in the public-school system. His talk was candid and honest, and it made me extremely excited to dive deep into Japanese culture and immerse myself with Japanese people. He encouraged us to live outside our comfort zones while spending the summer in Japan and try to do something new each day. He reminded us to pursue real connections with Japanese people, even if there is initial discomfort or language barriers in doing so. I hope to take his advice seriously this summer and immerse myself in this brilliant culture.

The highlight of my week so far has been attending a festival at Todai (The University of Tokyo), called 5月-さい (May festival). We were actually invited by a master’s student from Todai who we met during our visit to the University of Tokyo and discussion session with Tabata-sensei’s lab, to come, and I’m so glad we did. The festival was one of the largest gatherings of people in a small space that I’ve ever seen, and it was also one of the liveliest gatherings I’ve ever seen. The festival was unlike anything I’ve experienced in the US — the energy from all the people was so palpable in the environment. Hundreds of student groups and clubs from Todai had stalls selling street food, drinks, desserts, and other various items. There was an incredible student origami display, makeshift rock bands and their audiences packed into stairwells and classrooms, and an incredible J-POP performance in a main outdoor auditorium. My friends and I actually talked to a few Todai students there, and a couple of us even exchanged contact information to join sports clubs and such. To say the least, I wish that schools back at home had things akin to this. It was amazing to see the collective energy of this festival and joy that came because of it.

Language progress
Learning the Japanese language has been an absolute blast. I was placed in Class 2 with Trevor, and we’ve made so much progress in the past week with our many extremely kind and helpful language teachers. After the first day, I was surprised by how much of the Japanese I had previously studied that I recalled. Being immersed in the culture and context of Japanese seemed to have turned my brain “on” again for the language, and I have surprised myself at how well I’ve been able to communicate. It’s quite easy to get around if you have studied Chinese (which I have) and you can read katakana, which are characters that basically help you “sound-out” foreign words. Armed with these and a lot of Japanese I’ve practiced in class, I feel extremely confident in my very basic Japanese already. One goal I have moving forward is to become a more conversational speaker and pushing myself in class to ask questions that will promote casual conversation.

Question of the Week
I’ve heard a lot about “indirect speech” before coming to Japan, but I haven’t really noticed it much. Will this become something important to think about in a research setting? How can I pick up on “indirect speech” cues?

  • You may not have heard this yet as you are still a beginning language speaker and the indirectness of the language really does require more fluency with keigo and other polite forms. However, you may have noticed that you will rarely hear ‘No’ in Japan. Instead, you may hear someone say, “Hm, perhaps that maybe could be a bit difficult.”  Or simply a teeth sucking noise which may be as close as you come to a firm no.  You will likely encounter this in  your lab when, if you ask what time you should come to lab, some people may say things like, “It is up to you.”  To an American, you would likely accept this at face value but, in Japan, the correct thing to do would be to follow-up and ask, “Hm, perhaps it would be good for me to be at the lab when you are.  What time will you plan to be in the lab tomorrow?” as truthfully, your mentor may expect you to ask this and you should try to arrive a bit before they do.  You may also not get a direct answer to the question, “What time can I leave the lab?” in the same way.  Rather, you may just need to watch and observe when your mentor leaves that lab to get a better sense of what might be best given the culture/working times of your lab. It is indirect, because you are supposed to know that you should ask a follow-on question.  Also, people may not phrase thing as a specific request, but rather as a question or suggestion.  For example, “Perhaps we should move the tables into a square or classroom style. What do you think?” Here are a few more resources on indirectness in Japanese communication that you might want to also review.

Research Project Introduction & Paper Summary

 Before departure, we had an extremely thorough introduction to Japanese culture in the context of this research internship from both Sarah-san and Kono-sensei. Sarah-san’s lecture was extremely relevant because of her extensive experience running research programs abroad, and got me thinking about important goals to have while pursuing research that crosses cross-cultural bounds. Kono-sensei’s introduction to research was extremely exciting, and helped me understand that an undergraduate, with enough hard work and diligence, can definitely have a research impact in programs and collaborations such as these.

I have described many aspects of the planned week 1 sessions in my cultural overview above. One thing I didn’t include was a talk from Professor Nishikawa, a professor emeritus at Kyoto University. His talk was very intellectual stimulating, especially because of the passion it conveyed about the life sciences, a field that my studies were not focused on. It helped me consider that connections between my research interests in electrical engineering and physics and connect them to the grand challenges and opportunities facing humanity today, from the introduction of big data into peoples’ everyday lives to genome engineering to artificial intelligence to rapid international collaboration.

Another awesome thing we did was visit Todai and tour some of the amazing research facilities they have for nanofabrication and nanocharacterization. Tabata-sensei’s group was incredibly kind to give us this tour and talk to us afterwards, and I know we were all incredibly grateful for this opportunity. This trip really emphasized to me the raw power of collaboration, especially if Japan is involved, because its resources devoted to cutting-edge nanotechnology equipment is astonishing, especially compared to the much smaller equipment resources we have at Rice.

I am extremely excited to be working in the Matsuda Laboratory this summer, part of Kyoto University’s Institute for Advanced Energy. The Matsuda Lab specializes in optics at the nanoscale, and, according to Professor Kono, is one of the world’s finest labs in nanoscale material optics. This is somewhat familiar territory for me, as I’ve been a member of the Naik Laboratory at Rice University, which focuses on photonics (mainly plamsonic applications) of nanoscale materials. I’m excited to learn as much as I can about optics and materials this summer and bring all that I can back to my young group at Rice.

I have been assigned a PhD mentor in the Matsuda Lab, and my project will be focused on the optical properties of a class of two-dimensional materials called transition metal dichalcogenides (TMDCs). I am very excited for this opportunity because I have been doing research on two-dimensional materials at Rice (2D alternative metallic nanomaterials for visible-range plasmonic applications). Two-dimensional materials are classes of nanoscale materials that are either atomically-thin (monolayers) or contain very few atomically-thin layers (bilayers and few-layered ultrathin materials). The most famous example of a 2D material is graphene, and its incredible optical, electrical, mechanical, and thermal properties have led to a whole new paradigm in materials science, that of atomically-thin materials. 2D materials are extremely promising for use in optoelectronic applications. Because they are so thin, they interact very strongly with light. In addition, their thinness lends themselves to strong interactions with their surrounding environments, making gate-, stress-, and thermal-, and magnetic-tenability realizable.

Though the great majority of 2D materials research has focused on graphene, it has one downfall: it has no bandgap energy. (In most situations this has true; it can be tuned to have a bandgap energy through external fields, but this limits its high carrier mobility). 2D TMDCs are a solution to this problem: many of them (the most famous being MoS2) are semiconducting and have direct IR-to-visible bandgaps when they are monolayers. Direct bandgaps are wonderful for optoelectronic applications because interband transitions can satisfy momentum- and phase-matching conditions. The concept of bandgaps in semiconductors is what has led to essentially all of modern computing and technology: without bandgaps in silicon, gallium arsenide, and other popular semiconducting materials, the transistors, diodes, and junctions that rule our society would not be possible. 2D TMDCs offer a bandgap with all the benefits of the nanoscale.

Another reason that 2D TMDCs are interesting optically is because they have strong conduction-band valleys at separate points in reciprocal space. This is interesting for the field of valleytronics because electrons/holes residing in these valleys (conduction band minima/valence band maxima) can carry information in a new type of way. The momentum of the electron now carries information (what the valley the electron resides in k-space determines its momentum/wave vector). I was extremely excited to learn about this because the concept of valleytronics was extremely new to me. One amazing thing is that differences in circular polarization of incident light onto a material like 2D MoS2 can change the “valley polarization” of its current (the extent to which the current is distributed into one valley over the other), and that the valley polarization of the current can influence the circular polarization of photoluminescence! In essence, light (more specifically, light’s polarization) is the secret key to manipulate this novel way of transmitting information through different electron momentum in currents.

My PhD mentor has done work on 2D semiconducting TMDC monolayers and their excitonic properties. Excitons are bound electron-hole pairs (EHPs) that have a smaller binding energy than the interband energy gap but can have long carrier lifetimes in materials with high Coulombic interactions. Sometimes, if carrier interactions are particularly strong, trions will form (they do in MoS2 and MoSe2!) that have an extra carrier contained in them. I also am a total newbie to excitonics, but I am excited to learn about these carrier dynamics because of their important relation to valleytronics and other novel, futuristic schemes.

Paper Summary

Mouri, S., Zhang, W., Kozawa, D., Miyauchi, Y., Goki, E., and Matusda, K. Nanoscale (in press, 2017). Thermal disassociation of inter-layer excitons in MoS2/MoSe2 hetero-bilayers.

I will summarize a manuscript that has recently been accepted in Nanoscale that my PhD mentor contributed to on 2D TMDC excitonics in simple heterostructures.

One of the most exciting ways to utilize the 2D materials I have described in the above section is to exploit their extreme sensitivity to their environments in heterostructures (basically, many 2D materials layered on top of each other). This provides an incredible way to tune the optical and electronic responses of 2D materials by strategically crafting a proper 2D “sandwich.” These heterostructures are often extremely difficult to produce in practice, but are the topic of much research interest in the field. This paper describes the excitonic carrier dynamics that occur between monolayers of MoS2 and MoSe2. Excitons (and trions) in these materials have extremely high binding energies compared to traditional semiconductors, which makes them even more exciting for novel semiconducting applications. These new materials make the futuristic idea of excitonic circuits feasible, so it’s an extremely pressing issue to study their excitonic properties carefully.

The Matusda group used a technique called photoluminescence spectroscopy (PL spectroscopy) to study exciton dynamics in these simple 2D systems. This is an important technique that I’ve seen often in the literature that I have had no experience with and am excited to learn more about. Basically, PL spectroscopy relies on the way incident light (at different frequencies) interacts with a semiconducting structure with all sorts of energetic happenings such as interlayer transitions, excitonic/trionic excitations, and phonon modes. Much of the paper carefully argues that the lab has correctly characterized a unique inter-layer excitonic mode that occurs when monolayers of MoS2 and MoSe2 are stacked together. To do this, it was important for them to run all characterizations for the separate monolayers and for the bilayer structure. In addition, exploiting the unique tunability of 2D materials, they created a gate-tuning mechanism (similar to a basic MOSFET) that tuned the carrier concentration of the system. By tuning the gate voltage, they were able to characterize the nuances of the inter-layer excitonic response in this structure. I have had no experience with nanoscale device fabrication and would love to learn more about how they like to run experiments with gate tunability and fabricating basic devices.

Using such techniques, the authors were able to characterize inter-layer excitons and trions in this bilayer structure, including their decay time and binding energy. I would love to learn more about what simulation tools the Matsuda lab uses to compare their experimental observations to theoretical results. Simulation tools are powerful methods of exploring this new physics, and I would love to get a more theoretical understanding of this while I am a student in their lab this summer! I am beyond ecstatic to dive deeper into this area in one of the best optics and materials labs in Japan at one of the most prestigious universities in the world!

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Week 02: Trip to Mt. Fuji Lakes

Japanese language classes have still been a blast — Trevor and I have been learning many unfamiliar verb and adjective conjugations that have enabled us to construct more complicated sentences and questions. The highlight of this week in terms of language was visiting the office that our Japanese language teachers work at (AJALT) and having a 45-min Japanese conversation with a sensei we had never met. I gained so much confidence in my language abilities after being able to learn about and introduce myself to a completely new Japanese person! During our amazing weekend trip with the Japanese fellows, I was able to speak a decent amount of Japanese; this was super exciting! I could tell they really enjoyed when we try to speak Japanese, and often our broken Japanese helped bridge some communication gaps when neither party could find a word. Looking ahead, I want to improve my ability to talk about my research in Japanese, because many times I’ve been asked to talk about my research, but many English terms I use have been unfamiliar to Japanese people.

Good view: Enjoying the view of Fuji-san with JP Fellow Jumpei and US Fellow Trevor. ~ Alex Hwang

Weekend trip to Mt. Fuji Lakes
The weekend trip to the Mt. Fuji lakes area was by far the best experience I’ve had in Japan so far! Everything we did was so so incredible. After we met the Japanese fellows (the coolest people I’ve ever met, by the way) at our hotel, we traveled by bus to the 5th station of Mt. Fuji. After looking around, we had an amazing tempura udon lunch. We did some more sightseeing around Mt. Fuji, then had an awesome buffet (where I ate 30+ pieces of sushi) at our hotel. We got many of the Japanese and US fellows to go to onsen (traditional Japanese hot spring) together, which was an awesome bonding experience (no clothes allowed!) and so relaxing. Afterwards, we had all the fellows over for late night bonding in our room. It was a great time. On Sunday, we did a lot of sightseeing on the way back, from a beautiful bridge with a beautiful 360-degree view to a strawberry-picking farm. Oh, and we had lunch at the most amazing seafood barbecue/sashimi place I’ve ever been to.

Best lunch EVER: We had an incredible seafood barbecue with all the Nakatani Fellows together. ~ Alex Hwang

I was nervous before the weekend about meeting the Japanese fellows, but, from the beginning, they were so warm and open to us. We all started bonding instantly on the bus ride over, and it was (and is) clear to me that they are all so ridiculously amazing people. However, it wasn’t always easy to converse with them. Because the Japanese fellows had to meet not only the Japanese fellows but also the US fellows at the same time, I could tell they were, understandably, at times, overwhelmed with meeting and socializing with so many people. Even though all the Japanese fellows spoke perfect English, there were times when a particular English phrase or word caused some communication blocks. Mindful that many Japanese people can be taken aback by the eagerness of Americans to keep blabbing, I tried my best to navigate being my outgoing self and understanding when they preferred silence. Still, I do feel like I made some incredible Japanese friends this weekend and had many awesome conversations. I enjoyed every conversation topic, from physics to feelings of nervousness about going to a new country — I loved being able to connect to other university students from a completely different background, sharing similarities and bridging differences. This is one aspect that makes this Nakatani program so unique and special. I learned much about how universities in Japan operate and how they compare and contrast to US universities. I was especially interested in the Japanese fellows’ opinions on hierarchy and how undergraduate students fit into the academic hierarchy here. Not only did I make some amazing friends, I also got to learn so much about Japanese universities from the best source possible: Japanese university students themselves.

Two legends: Yet another selfie with the legendary Sarah-san and Ogawa-san, without whom this amazing program would not have any chance of running smoothly. ~ Alex Hwang

Overview of Week Two of Orientation Program
This week, even before the Mt. Fuji lakes trip, was a whirlwind of activity and fantastic outings. On Monday, we visited JAMSTEC, a “Marine-Earth Science and Technology” center that does advanced research on earthquakes, an extremely pertinent issue to Japan. It was fascinating for me to see how much advanced algorithmic signal processing and network engineering that goes into dealing with this problem that has such tangible connections to people and their well-being. On Wednesday, we had a lot of fun at a Taiko drum workshop (but ended up with very sore arms afterwards). Afterwards, I introduced the Japanese cultural cornerstone that is UNIQLO to dad for the first time. (Aaron is now known to both the US and Japanese fellows as “Dad” because he is the perfect archetype of a dad).

On Thursday evening, we had a wonderful discussion about bridging cultural differences, led by our one and only leader, Sarah-san. I loved getting the chance to meet even more Japanese students and discuss. Afterwards, some of us all had a lovely ramen late night snack together! It struck me when I asked one female student why she didn’t want to be a professor and she replied, “Of course I don’t want to be a professor? There’s no way I would fit in.” This was the first immediate moment for me where I began to think about the complicated relationship between science and culture in Japan.

Our final cultural session of the week was a guest lecture about the kimono, its historical significance, and ways of bridging the traditional and the modern in Japan’s current and future society. This talk was one of my favorites that we’ve listened to, and I was so inspired by our speaker, Kento Itoh, his vision for connecting the world with the kimono and his encouragement for us to think about and connect with culture on a daily basis.

Question of the Week
A lot of the Japanese fellows I met this week told me that they were much more interested in being researchers in industrial/governmental labs than academics. Is there a big difference between the work preferences of researchers in Japan and in the US? Is being a research scientist in Japan at a prominent lab like RIKEN more prestigious than being an academic?

 Introduction to Science & Engineering Seminars
This week, we had two awesome introductory science seminars. On Tuesday, Kono-sensei gave a brief review of basic materials science concepts. Though I’ve seen most of these topics before, Kono-sensei has a wonderful way of fitting many ideas into a clear story. He elegantly combined basic science concepts with practical ideas and questions for us to consider going into materials research. Then Itoh-sensei from Keio University gave a fascinating lecture about quantum computing, a topic that I really should know more about given that I’m a photonics and nanoelectronics major at Rice. I enjoyed Itoh-sensei’s talk because it covered the broad scope of quantum computing from identifying a problem to mathematical theory to solve such a problem to implementing a solution using basic principles of quantum mechanics. I was especially interested in one topic he covered: using the Fourier transform to “un-superimpose” the states of many qubits in order to unveil the calculations performed/information transmitted. I’ve taken several signal processing classes so this part was particularly interesting for me, and I’m curious to know exactly how such a FT would be performed. Itoh-sensei mostly talked about using spin for quantum computing, but I’m interested to know how controlling the valley degree of freedom fits into this story (my research project this summer has many relevant connections to optical valleytronics).

On Thursday, we had Kono-sensei give an overview of QM and nanoelectronic/nanophotonic applications. Again, this was a wonderful way to review some basic science concepts and I’m always looking to improve my knowledge of the most important papers, results, and scientists in this field. After this, we listened to a lecture from Kawata-sensei from Osaka University on nano-bio-photonics, which I was thrilled to listen to. It may have been one of the best lectures I’ve ever listened to, and was so inspiring for me to think about the way my interest in photonics can have impressively many applications to emerging biomedical innovations. After this talk, I definitely want to do more research into this field as the results he presented to us were so intriguing and thought-provoking. In particular, I was especially interested in the portion of his talk he spent talking about how at some period in career, he was frustrated with investing so many resources on top-down fabrication of metamaterials, so he instead tried to pursue bottom-up synthesis of metamaterial structures that mimicked structures found in nature such as snowflake crystals.

Weekly Paper Summary
This week I was only able to read one paper, but I tried to read it very carefully since it seems to be very well-cited in the relevant literature for my project.

Mak, K.F., He, K., Shan, J., and Heinz, T. F. Control of valley polarization in monolayer MoS2 by optical helicity. Nature nanotechnology (2012).

This short paper from the Prof. Tony Heinz (at the time, located at Columbia) details optical measurements that suggest ways to dynamically control the valley polarization for long retention times (1+ ns) of monolayer MoS2 samples using the circular polarization of incident pump light. The basic idea is to exploit the broken inversion symmetry of MoS2 (absent in other prominent 2D materials such as graphene), which allows for photon angular momentum to control valley population. In non-centrosymmetric materials like MoS2, valley-spin coupling leads to split spin degeneracy. As a consequence, optical selection rules are defined for both interband and excitonic transitions at the two main valleys found in the MoS2 band structures. In effect, this valley-spin coupling leads to strictly defined ways of exciting a particular interband or excitonic resonance in the different valleys found in MoS2. The Heinz group conducted broadband absorption and photoluminescence spectroscopy on monolayer MoS2 samples, demonstrating two strong excitonic resonances, both in about the middle of the visible range (1.9 eV and 2.1 eV). The lower energy exciton has much higher relative photoluminescence intensity. To develop this argument further, the authors conducted various specific photoluminescence experiments at specific photon pump energies, and showed in a convincing manner that intelligently pumping valleys with the required circular polarization resulted in extremely high degrees of polarization of the photoemitted light. These findings in monolayer MoS2 are contrasted with those of bilayer MoS2, which has inversion symmetry and produces significantly lower degrees of polarization of photoemitted light, supporting the authors’ argument that inversion symmetry allows for this unique phenomenon in the monolayer limit. These strong results were demonstrated on both hBN and glass (Si/SiO2) substrates.

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Week 03: Noticing Similarities, Noticing Differences

 I am writing my cultural reflection as I sit, for the first time, in the amazing innovation that is shinkansen (bullet train). Just when the time on Kaylene’s computer switched from 11:59 to 12:00, the train leapt from the station. The shinkansen’s timeliness, practicality, and efficiency aptly captures the spirit of Japan I have noticed so far this summer.

Sushi: I got Dad (Aaron) to try soft-shell crab sushi. Safe to say that he liked it! The place we went to was recommended to by one of our favorite AJALT teachers, Onishi-sensei. ~ Alex Hwang

Japanese public transportation, in general, is amazing and unlike anything I’ve seen in the States. The first thing to note, as in the shinkansen example, is that every train, subway, or bus always arrives and departs on-time. This sense of order and form, represented in Japanese as 型 (kata) permeates multiple layers of Japanese society from the transit system to the timeliness of every meeting and appointment. Of course, this is very absent in most places in the US, especially in the two places I call home: laid-back California and relaxed Texas.

Moreover, it is the people that really make the difference in this system. There are several unwritten rules that people seem to follow on public transportation. For one, Japanese people on public transport almost never talk, and when they do they are barely audible. Our group of students is always the loudest on the train. Japanese people are always mindful of how much space they are occupying, whether they are sitting or standing. Because of this, I decided to buy surgical masks to wear because I was getting some dirty looks from Japanese people when I coughed on trains. All this point to 和 (wa), the sense of order the binds together Japanese society. For Japanese people, it is critical to act to promote the group interest, which contrasts with the rugged individualism I’m familiar with from back home.

However, one problem with the subways is that they can get extremely crowded, and you can often observe squeezing to the extreme to fit everyone on a single train. Even Japanese people look visibly uncomfortable when this happens. Evident here is the tension between Tokyo’s bulging population and the desire for harmony and order.

It’s interesting to see almost every Japanese person on a subway train either asleep or on their phone. I’ve even often seen people trying to sleep while standing up. I rarely see Japanese people chatting with each other. More broadly, I’ve noticed this throughout Japanese life in general. As we were told, chit-chat is a lot less common here, which is something I’ve come to appreciate. Though I’m a talkative person, I like taking moments to appreciate silence now and then.

Overview of Week Three of the Orientation Program in Tokyo
I definitely took a breather this week because the Mt. Fuji trip was tiring and I started getting feeling pretty sick. Of course, I still have several highlights to share. Though the biology section of his talk went over my head a little bit, I really enjoyed listening to Dr. Gert-Jan Bekker from Osaka University talk about his experiences being a long-term international researcher in Japan. His use of Japanese with Endo-san and Ogawa-san was impressive, especially considering that he came to Japan with very limited Japanese. He offered many useful tips, such as finding online language buddies, that I plan to use in the future to help me study both Japanese and Chinese.

My favorite cultural talk of this week was from Dr. Kunie Ishioka, leader of the optical characterization group at the National Institute for Materials Science (NIMS). She inspired me with her story of pursuing her dream of science in a country that so stiffly opposes women in academics and science. It was shocking to hear some of the statistics she quoted regarding women in higher education and science in Japan. Just a few decades ago, even if you were one of the few Japanese women to obtain a PhD in science, you could essentially be blocked out from getting an academic position. Academic positions were often solely based on connections, and the male-only club of academia would be hard pressed to offer a position to a woman. Her talk motivated me to stick close to my scientific goals and dreams, and persevere in spite of the many challenges that being a researcher brings.

I also enjoyed Dr. Don Futaba’s talk about being an original second-generation Japanese-American who moved to Japan after obtaining his doctorate. Hearing his experiences really resonated with me especially because we both grew up in the same area in California and we are both second-generation Asian-Americans who have to deal with the expectations that that gives rise to.

Ghibli Museum: Visiting the Ghibli museum was one of the most phenomenal experiences I’ve had in Japan. This is a must-visit for anyone who’s seen any of Hayao Miyazaki’s movies. ~ Alex Hwang

Since the start of this trip, I have been enjoying watching many popular anime films in a group, including Kimi no nawa (AMAZING MOVIE, by the way!), Koe no kotachi, and The Girl Who Traveled Through Time. It’s also impossible to miss the influence of anime and manga when walking around Japan, especially in areas like Harajuku and Akihabara. Because of this, I really enjoyed listening to Dr. Saeki of DŌshisha University discuss the evolution of the role of women in popular Japanese media. I know it’s difficult in Japan to be a female academic, let alone a female academic whose work centers upon condemning the Japanese patriarchy. Dr. Saeki’s work is extremely important and relevant — it helped me connect my observations about the gender gap in science to the role of women in culture and media.

For the basic science overview this week, it was nice to review with Professor Stanton some basic solid-state physics and solid-state electronic applications. I really learned a lot from his lecture on femtosecond spectroscopy techniques; he presented it in a simple manner that made it very intuitive to understand. Dr. Ishioka expanded on this by presenting how experimental work at NIMS in femtosecond spectroscopy for materials characterization, with a particular example being characterizing novel perovskite solar cell materials. Dr. Futaba gave an overview on the basics of CNTs and CNT synthesis.

Question of the Week
One thing I’ve been surprised to learn about in Japan is that most Masters students apply to jobs in industry and are not interested in a doctoral degree, as many industrial jobs want masters graduates, not doctoral graduates. Still, those students interested in a doctoral degree must get a Masters degree first. Do these masters students have a different role in the lab than the Masters students that just want to go to industry?

  • Good question, and this is something you may be able to learn more about by talking with your lab mates in Kyoto and/or speaking with Prof. Kono or the other Japanese Fellows about.  In the U.S., students who get a PhD also must get a Master’s first but it more common to directly enroll in the PhD program and then get your Master’s along the way.  For example, you are admitted to the PhD program in Electrical Engineering and after you complete your coursework and pass the qualifying exam/course you can submit your Master’s thesis and then advance to PhD candidacy. Some U.S. students even walk through graduation twice, once when they receive their Master’s and again when they complete their PhD as they want to mark each of these milestones.  This also means that, if for some reason, a PhD student realizes along the way that maybe completing a doctoral degree isn’t the right path for them they can stay as long as it takes to get their Master’s and then leave the program with a degree in hand.
  • However, there are other science and engineering Master’s program in the U.S. that do not require research or a thesis.  At Rice University, these are called Professional Master’s degrees. Non-research based science and engineering master’s degrees are often targeted at students who have worked in industry for a few years return to school to complete a Master’s degree (often with partial or full funding from their employer).
  • In Japan, all Master’s students take coursework and do research.  They usually stay at the same school they received their Bachelor’s degree from and typically also stay working in the same research lab that they began doing research in during their B4 (senior) year.  In this way, they actually spend a total of 3 years working with the same group even though they only do research as a graduate student for two.  One of the primary differences might be that at the end of their Master’s degrees, students who plan to go into industry will begin spending a lot of time on job hunting whereas students who plan to go on to complete their PhD may be able to stay more focused on research – until they near the end of their PhD at which point they may spend more of their time on job hunting either for positions in industry or academia.  
Yum: My first priority in Kyoto was to cook a whole pot of rice for the week. ~ Alex Hwang

Research Project Update
Because it’s late, I’m going to save a detailed discussion of my project for next week’s report, but today was my first day in the lab and it was so exciting to discuss my project in detail with Miyauchi-sensei. My project involves optical measurements to probe the exciton relaxation dynamics in monolayer WSe2. After a warm initial welcome to the lab at our group meeting this morning, I met with Miyauchi-sensei for about an hour and a half, then got right to work. I hope in the next few weeks to learn how to use all the major equipment, and successfully fabricate a particular heterostructure that I will make optical measurements on. If I can accomplish this soon, I will have plenty of time to make some measurements. Today my mentor Zhang-san taught me how to mechanically exfoliate monolayer WSe2 using the Nobel-prize winning Scotch-tape method and confirm its thickness using Raman spectroscopy. After that, I was able to successfully exfoliate a monolayer on my own! I’ve begun tackling a long-list of exciting, albeit challenging, papers that will hopefully help me understand the basic physics behind exciton dynamics in these TMDC monolayer materials. Moreover, I could not be more ecstatic about the group that I joined — they welcomed me so warmly with open arms. More on that next week!

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Week 04: First Week at Research Lab

Bakery-heaven: I’m always tempted to put this as my weekly “cultural question”: why are the bakeries here all so amazing? Kaitlyn and I tried out the bakery chain that supposedly was the first to imitate the Paris-style bakery in Japan. ~ Alex Hwang

I am now a part of the Matsuda Lab! It’s officially been a week since I’ve started, and I’ve had a blast while working very hard. On the first day, I arrived just in time for the weekly group meeting, where I was introduced to the entire group. The style of the group meeting was much different from what I was used to in the US; every member reported to the professor, associate professor, and assistant professor with their research progress in the past week and what they planned to do in the coming week. In the US, it seems like group meetings last at least 2.5-3 hours, but the Matsuda group’s meetings are efficient and to-the-point, 1 hour long meetings. I really like this aspect of the group because it allows the entire group to be updated on others’ progress and encourages everyone to strive for incremental progress and set goals.

After this, I met with my PhD mentor, Zhang-san, and my associate professor, Miyauchi-sensei, to talk about my summer research project. He very clearly outlined his goals and expectations for me, and after about an hour and a half meeting with him, I got to work! These two mentors have been instrumental in getting me familiarized with the lab quickly. In fact, the entire lab has helped me many times with various equipment and procedures. I’ve quickly realized that I love being in a large lab group setting common at somewhere like Kyoto University but not at a smaller school like Rice. This is something I will continue to think about this summer and next year when I apply to grad school.

1. Arashiyama Monkey Park: On my day off, I had an amazing time exploring the Arashiyama area in Kyoto with Kaitlyn, Will, and Savannah. ~ Alex Hwang

My assimilation into the lab has been super smooth because the research they do is similar to my lab at Rice, and English is the primary language of communication in our very international lab. Basic communication and science communication is usually easy; more conversational communication is a little difficult, but I can usually manage with a combination of broken Japanese, Chinese, English, and gestures.

My housing at the Mukaijima Gakusei Center is awesome! I bike to work with the used bike I bought nearby, and it’s very close to everything. Because I’m not in Kyoto city but a more suburban area called Mukaijima, my bike route to lab crosses many rice paddies and gorgeous mountain/river landscapes that could not contrast more with the city landscape of Tokyo.

After having spent a week in my new home, Kyoto, I am very thankful for the 3-week orientation we had in Tokyo. I use much more Japanese here than I did in Tokyo, because I live in a fairly rural area, so people outside the lab don’t really speak English. I definitely would feel more like an outsider and uncomfortable in this situation had we not spent time in Tokyo to discuss language and culture together. Additionally, I’ve never lived on my own before, so shopping and cooking for myself is definitely a new adventure! Already, I feel more confident in my ability to live independently. Time management is something I’ve always prided myself on, but I’ve been surprised with how much I’ve improved in this regard since coming here. I’m lucky that I have a lot of independence over my research project, so I decide when I come to lab. Usually I come at around 10 AM and stay until at least 11 PM – midnight. I’m definitely not slacking off, but I’m having so much fun with research and life in Kyoto!

Question of the Week 
Probably the only complaint I have is that the Uji campus is very geographically separate (an hour by train) from the main Yoshida campus, where all the clubs, libraries, gyms, etc. are. Is there a reason besides space that so many Japanese universities are partitioned into several different campuses?

  • Usually, one of the campuses is more of the undergraduate campus where students take classes and, therefore, this is the campus that undergraduate student life tends to center around.  Other campuses may have a specific focus on an area of research and are where the graduate schools and research laboratories/institutes are typically located. Remember, undergraduates only do research in Japan as part of their B4 year so there isn’t such tight integration between graduate and undergraduate life as you see at places like Rice where undergraduates, even freshman, are working in research labs alongside graduate students. If you look at the university structure, you will also see that there are Graduate Schools of Engineering or a Graduate School of Science rather than one School of Engineering or School of Natural Sciences that encompasses both undergraduate and graduate education.  Therefore, even within the structure of the university there is a split between undergraduate and graduate education.
  • Also, as universities grew, especially to accommodate the baby boom following WWII and increased demand for higher education in the 70s and 80s, they didn’t have much physical space in their central, in-city locations to expand.  Population densities can be very high in cities in Japan and land is very expensive.  Since universities in Japan have, historically, been almost wholly funded by the government they would often be assigned/purchase land at discounted rates in more rural areas where they could develop new research facilities. This also gave an economic boost to the more outlying areas of the city, bringing jobs and increased demand for housing/services in the area.  So, from a government policy initiative there were multiple benefits to expansion of university campuses to locations outside of the city center.
  • You may also want to ask your host professor about this and if he, or the assistant or associate professors in his lab, teach or have much interaction with undergraduate students. You can read more about the history of Kyoto University, and your particular campus, to better understand its expansion.

Research Project Update
My research project deals with a particular 2D semiconducting transition metal dichalcogenide material, tungsten diselenide, WSe2. In the monolayer limit, WSe2, like other well-known 2D TMDCs, is a direct bandgap semiconductor, which means it has great potential for use in optoelectronics. Monolayer WSe2, like other semiconducting TMDCs, also has been discussed often in the emerging field of valleytronics. In 1L-WSe2, broken inversion inversion symmetry leads to spin-orbit coupling and broken valence band spin degeneracy at its two main “valleys” in reciprocal space. This leads to the ability to selectively populate either of the two valleys using the circular polarization of incident light. In 1L-WSe2, excitons (bound electron-hole pairs) dominate the optical activity, and it is these excitons that can populate the valleys. Current researchers can easily measure valley polarizations in 1L-TMDCs at close to 100% using polarization-resolved photoluminescence spectroscopy. However, much less is known about the basic physics behind valley polarization and the dynamics that happen between exciton excitation and complete loss of valley polarization. Recently, my lab has done a lot of theoretical work to supplemental their experimental studies to probe the physical mechanisms behind valley relaxation, the process of losing valley polarization, in 1L-TMDCs.

My research project this summer is to synthesize a special 2D material heterostructure (that includes WSe2) and characterize it using time- and polarization- resolved photoluminescence spectroscopy. In other words, I need to synthesize a very special heterostructure, or sandwich, of 2D materials that I hope will lead to a longer valley polarization lifetime than has currently been reported in the literature, which is a hope based on work my lab has done in developing a unified theory of exciton relaxation dynamics in these materials.

On Saturday, I synthesized the heterostructure in question, and will learn how to measure it in cryogenic conditions on Wednesday, but based on some room temperature analysis I made today, I’m guessing that the sample I created wasn’t of high enough quality. Because of this, I hope to spend the next week and a half or so perfecting my sample synthesis. After that, I will hopefully have multiple high-quality samples that I can characterize under cryogenic conditions. The measurements I plan to run are time- and polarization-resolved photoluminescence spectroscopy.

It’s only been a week, and I feel I’ve learned so much about being in a lab, especially with the amazing amount of equipment they have here. Sometimes the equipment is pretty challenging to use because the software is all in Japanese! Thankfully, I have amazing lab mates who never tire of helping me often. So far, I’ve learned how to use the Raman spectrometer, room temperature photoluminescence spectrometer, 2D material mechanical deposition system, and atomic force microscope. I haven’t spent any time in the optics lab yet, but hopefully if I can create some high-quality samples, I will learn a lot about lasers and optics, which I have basically zero experience in. In terms of chemistry, I’ve only done basic 2D material sample preparation by mechanical exfoliation (the “Scotch tape” method that won the Nobel Prize!), which is definitely an art and an exercise in patience. I’m definitely a little bit of a clumsy and sloppy chemist, so this is definitely something I hope to improve on this summer!

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Week 05: Critical Incident Analysis – Life in Japan

1. An “Ogawa Coffee” Katelyn and I found while exploring Arashiyama last Sunday. Legend says that it is named after Kennji Ogawa, who also works at the Nakatani Foundation. ~ Alex Hwang

Back home in America, I feel that I can usually make friends quite smoothly, especially if I find out that they have similar interests as me and we share things in common. This week, my critical incident analysis of a situation with differing cultural perspectives happened while trying to make friends with a student studying at a nearby Kyoto university. This was my first real experience making a Japanese friend outside my lab since coming to Kyoto.

I’m super lucky that my student residence center, the Mukaijima Gakusei Center, often hosts events for international students. Last Friday, they hosted their weekly Japanese language class, where college students from nearby Kyoto Bunkyo University cme and help us with Japanese. My sensei was a college freshmen, who was very kind and connected with me very easily. Because during the lesson, he told me that he loved McDonalds, I invited him to go to McDonalds with me for dinner. After all, I had not made any Japanese friends outside of lab yet, having been in Kyoto for less than two weeks. We had an awesome time at dinner, and it was easy to relate with him, as we are of similar ages and both university students.

However, I ran into sometime significant cultural difficulties in navigating a situation that is so commonplace back home. First of all, there was definitely a language barrier between us, and I tended to keep nodding my head and saying “hai!” when he would ask me a rapid question in Japanese. I didn’t want to keep interrupting him and asking him to repeat or slow down or try the question in English. This almost felt like when you’re in class and keeping nodding your head to a lecture, even when you only understand half of it, and by the end you feel really confused. In attempting to hide my foreignness, I made communication much more difficult than it would’ve been if I had asked to slow things down.

1. An awesome new friend I met on Saturday while playing basketball during a break from work. His dream is also to be an American professor, and it was very nice having him help me navigate the menu of a very tasty lunch spot. ~ Alex Hwang

I’ve learned from the pre-orientation speakers and discussion sections that socializing in Japan can be much different than in the United States. Many peoples show two totally different sides of themselves when, for example, they’re with friends at work or with friends at a restaurant. In Japan, people hardly ever invite you to their home unless you’re much older, which probably has something to do with small room sizes. I was cognizant of all this at the time. For me, this made me wonder whether I could use the same college student phrases such as “Hey, we should definitely hang out some time. Wanna get dinner tomorrow?” that I use almost every day in America. For one, I’m not even sure if “hang out” translates into any other language besides teenage English? Also, and this is especially true with women, I’m usually not sure if making a statement like that with a Japanese woman will make me appear like I’m asking them out on a date. In America, where I’ve grown up my entire life, it’s easy for me to understand the nuances of “Hey, we should get dinner tomorrow,” but in Japanese, I often feel that I have no idea what the connotations of what I’m asking are.

Erica (2016 Nakatani RIES alumna) led Katelyn, Aaron, and me on a fantastic tour of the food scene of Osaka yesterday. I don’t think I’ve ever eaten so much good food in my life. This picture is from a famous okonomiyaki place in Dotonburi. ~ Alex Hwang

Regardless, I think that I successfully made a pretty awesome Japanese friend on Thursday and I hope I will see him again soon. This was a valuable experience for me to reflect upon all the cultural assumptions and understandings submerged in the metaphorical “cultural iceberg” that I would never have thought about being just in America. I know that the only way to make myself more comfortable in these situations is to have more practice. Situations like these definitely put me outside my comfort zone a little: in America, I usually find it very easy to make friends as an extroverted person, but in Japan, I am constantly thinking about each word I say. But such experiences are perfect examples of why cross cultural-communication can be both difficult and rewarding, in terms of personal growth and the ability to form meaningful relationships with people.

Research Project Update
I made a lot of great strides with my research this week and also learned a lot about working in an experimental laser spectroscopy setup.

I continued my construction of 2D material heterostuctures, and made a sample that I hope to test next week at 10 K that looks to be very promising based on the room temperature photoluminescence spectrum that I measured. I’m learning quickly that having a large lab group can be awesome for all the knowledge and resources that I’ve praised in past reports, but it can also be frustrating when you have multiple people wanting to use the same laser setup. This is why I made my sample last week but can only test it at the soonest in another week from now.

I tested the first structure that I built during my first week in the lab at 10 K, doing basic polarization-resolved photoluminescence spectroscopy as a function of excitation power to observe the effect of exciton density (excitation power) and how this effects linewidth and other important characteristics of the excitonic spectra. Unfortunately, my sample looked to have a good amount of surface defects, as the defects and other “localized states” kept saturating the spectrometer. Regardless, Miyauchi-sensei told me that my experiment had very good results and helped them understand how their theoretical work plays out on the experimental side. Also, it gave me a lot of experience navigating our complicated low-temperature, polarization-resolved laser setup, which has a lot of optical components. While I am still in the mode of watching my mentor handle the complicated laser alignment, I am gaining much independence and ran the actual experiment by myself. After this, I conducted a lot of analysis on this spectral data in MATLAB and presented my results in group meeting today.

Besides this, I have been reading many papers that are trying to build similar 2D material heterostructures as we are, and have finally suggested to my lab that we update our setup for creating heterostructures. I think it would greatly benefit our lab if we followed the lead of these papers to use an additional polymer film (which I successfully synthesized today by simply dissolving in chloroform) and the ability to heat our heterostructure stage to a specified temperature. This will allow our lab, hopefully, to build complicated structures with more precision and less contamination. My lab seems very open to the idea, and I hope to start building this setup soon. The only frustrating thing, of course, is that ordering many different parts and chemicals, of course, takes time, and not everything can be shipped from Japan.

Other than that, I hope to continue making samples and test some of them next week at low temperature! Also, I still only know the basics of how to manage our time-resolved ultrafast spectroscopy setup, and I hope to run these more sophisticated measurements next week also if my samples look any good.

 

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Week 06: Preparation for Mid-Program Meeting

Coming this summer!

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Week 07: Overview of Mid-Program Meeting & Research Host Lab Visit

Coming this summer!
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Week 08: Research in Japan vs. Research in the U.S.

Coming this summer!

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Week 09: Reflections on Japanese Language Learning

Coming this summer!

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Week 10: Interview with Japanese Researcher

Coming this summer!

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Week 11: Critical Incident Analysis – In the Lab

Coming this summer!

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Week 12: Final Week at Research Lab

Coming this summer!

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Week 13: Final Report

Coming this summer!

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Follow-on Project

Coming this summer!

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Tips for Future Participants

Coming this summer!

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