Graduates Voice

Yoo Sakuma
Mr. Yoo Sakuma
The year of graduation from JAIST: 2014
Director of Sakuma Corp.
【Research at Ohdaira-Lab】

“Fundamental properties and solar cell performance of solution-processed a-Si:H”

Please introduce your present job

 After three years’ working experience in another company, I joined Sakuma Corp., the company that my father was running, as a director in 2017. Our company provides equipment works including renovation and water-supply works. Now I am mainly in charge of sales and corporate planning. In sales, I am hearing our customer’s desire, choosing suitable equipment, and planning the schedule with outside suppliers. In corporate planning, I am discussing with CEO, my father, what business we should focus on and how to motivate the employees under today’s social situation such as decrease in population and labor shortage.
 I feel this work is rewarding for me especially when our customers are satisfied with our works and give us thanks. As our company deals in necessary equipment for daily life such as water-supply, electricity, gas and gasoline, I often realize our business is necessary and important.
 Although I am not a researcher now, the knowledge on solar-cells technology learned in Ohdaira-lab is still so helpful. Since my company provides works of solar panels as well, we are paying attention to recent solar energy’s trend and considering our future strategy. When I am searching related information by a seminar and website, the understanding of renewable energy and solar cell’s principle helps a lot.

Why did you choose Ohdaira-lab?

 I had been studying the development of 2ZnSnS4 (CZTS) solar cells formed from liquid materials when I was an undergraduate student, and got more interested in Si, the material widely used for solar cells. At that time, JAIST was well known for the research on liquid Si and Ohdaira-lab was one of the laboratories doing the related studies. In addition, the main research in Ohdaira-lab was the development of solar cells that was linked to my own theme. That is why I enter JAIST and Ohdaira-lab.

What was your research theme in your master’s course?

 My theme was the fundamental study on the development of solar cells using liquid Si. I evaluated the property of amorphous silicon (a-Si) films formed from liquid Si mainly by Raman spectroscopy. The a-Si films can be formed, at atmospheric pressure, by coating and annealing Si ink formed from cyclopentasilane (Si5H10) — liquid-phase Si-based compound at room temperature. My research goal was to find out the difference of the property between a-Si formed by conventional chemical vapor deposition (CVD) and that by liquid Si and to realize an improvement in the efficiency of solar cells.

The memory of your student life in JAIST and Ohdaira-lab

 Thinking back to my student life in my master’s course, I do not feel I had so big hardships. Of course, I was working very hard on my study, doing experiments, writing papers and practicing for the presentation in conferences. However, when I was facing a problem, Prof. Ohdaira gave me helpful advice and other members also supported me a lot.
 In Ohdaira-lab, we had a lot of practices for presentations before conferences, in which we learned how to speak to an audience, how to make eye contact and performance, and how to summarize the contents. These practices helped me to improve my presentation skill. In writing paper, we got detailed advice and learned the basics of writing such as the structure of sentences and the choice of exact words. All of these skills acquired in Ohdaira-lab are very helpful in doing my current job.

 I really think I had fulfilling days in my student life outside laboratory too. I enjoyed BBQ, travelling, and eating out with other students in weekends. As workout had been strongly recommended in Ohdaira-lab, we often enjoyed playing tennis in late afternoon. That helped me to refresh myself during researches. A year-end party with other laboratories was one of fun memories too. There were a lot of good hot springs near JAIST, and we enjoyed one of them and stayed overnight. JAIST softball tournament was also really fun. I participated in planning and running the event with other members in Ohdaira-lab. I myself liked playing baseball and I was glad that other students looked enjoying the event.

Message and advice for students who have an interest in Ohdaira-lab

Yoo Sakuma

 Prof. Ohdaira is a very enthusiastic supervisor. You can learn so much knowledge and techniques by studying hard in this laboratory. Also, the students in Ohdaira-lab have many chances to participate in conferences and exhibitions. They must be good experiences to discuss with other researchers and listen about their studies too.
 In the master’s course, I think, it is important to communicate and connect with other students as well as concentrating on your research. Research life while living alone in dormitory is sometimes a battle against loneliness. At such times, relationships with surrounding people definitely help and support you. Luckily, there are a lot of famous places to visit in Ishikawa prefecture. Enjoy visiting these places and of course, do your best in your studies as well, then your student’s life in JAIST must be wonderful.