A torchbearer for the future of applied materials and optoelectronics — Professor Hsiang Chen (陳祥)
For those unfamiliar with the terms “applied materials” and “optoelectronic engineering,” a few keywords such as “semiconductors” and “sensors” should jolt one’s memory. The importance of this cutting-edge field can be illustrated by examining recent Nobel Prize winners and their research.
First, three Japanese researchers were jointly awarded the 2014 Nobel Prize for Physics "for the invention of efficient blue light-emitting diodes which has enabled bright and energy-saving white light sources," for they held the key to the elusive blue LED — Gallium nitride (GaN).
Another pair of laureates, both of Russian heritage, were awarded in 2010 "for groundbreaking experiments regarding the two-dimensional material graphene." Graphene is a newly discovered form of carbon that is prized by manufacturers of touchscreens, light panels, and solar cells for its superior transparency and heat-conducting properties.
Hsiang Chen, chair of National Chi Nan University’s Department of Applied Materials and Optoelectronic Engineering, began his academic journey in the field of electrical engineering before delving into photonics and nanomaterials. His alma mater, National Taiwan University’s fiercely competitive Department of Electrical Engineering, has been the top choice for Taiwanese students taking the university entrance exam for the past decades.
After rigorous training through NTU's undergraduate and graduate programs from 1991 to 1997, Chen left Taipei to pursue a doctoral degree at the University of California, Irvine from 2005 to 2008. It was here, in a dimly lighted campus laboratory, that he first caught a glimpse of the imperfections within the GaN transistors of that era. He proceeded to dedicate his thesis to this discovery, and graduated with both a Ph. D. degree and a book offer from a German publisher.
“At that time, researching GaN transistors was a new field,” the distinguished professor explains. “These high-power transistors are used in cellular towers, satellites, and even in outer space, but [the design then] lacked stability and contained structural flaws that could be rectified by optoelectronics.”
The materials used in his doctoral studies were procured from an American arms manufacturer that crafted F51 fighter jets and is now known as Northrop Grumman, a global aerospace and defense technology company. Unable to secure a source for such transistors upon returning to Taiwan, Chen turned his attention to the more readily available zinc oxide (ZnO) nanoparticles.
Described by the professor as “structurally identical” to the hexagonal columnar basalt found on Taiwan's Penghu Islands, crystalized ZnO particles are actually a million times larger in terms of mass. This stretch of surface is extremely advantageous in making light, portable nano-sensors that can be used to reliably measure carbon monoxide levels or ultraviolent rays.
Chen compares the process — that of introducing nanomaterials to zinc oxide to create completely new ZoN nanostructures — to “changing the toppings on a subway sandwich” to refine the properties of the end product differently each time.
Respected among his peers as a well-trained engineer who has never ceased his research efforts, Chen maintains a steady publishing average of 8 articles per year in international science master journals listed on the Science Citation Index (SCI).
This track record is matched by only a handful of NCNU faculty members, however Chen humbly redirects the compliment instead to acknowledge the collective hard work of the optoelectronics department’s instructors and student researchers.
He interjects: “There is a student who is working on those fresh perovskite [solar] cells, heard it was similar to Intel’s research.”
Chen took up the post of departmental chair last year upon completing a sabbatical and visiting at the research lab of Yale's acclaimed Professor of Technological Innovation Jung Han (韓仲). Apart from livening up his department’s recruitment and teaching process, he is also leading the way for more case studies, hands-on experiments, and industry knowledge such as the latest breakthroughs in technology and applications.
One of his recent lectures was on optical tweezers invented by the 2018 Nobel Prize in Physics team that grab atoms, molecules, and DNA with laser beam fingers; the lasers push small particles towards the center of the beam and hold them there.
The professor dutifully recites the tremendous employment opportunities that come with a bachelor's degree in the field: Taiwan Semiconductor Manufacturing Company (TSMC), United Microelectronics Corporation (UMC), Micron Technology, and Epistar. Other graduates opt for further studies at institutions such as Carnegie Mellon and Duke.
Two recent graduates are now serving as research engineers at TSMC, he says, drawing attention to the importance of deep familiarity with both the compositional and modular properties of semiconductors. “Having a background in manufacturing and sensor-testing semiconductors, as well as knowledge of the physics and materials used, will open up a lot of doors in both the electronics industry and the optoelectronics field.”
Academic-industry cooperation on a community level is another passion of Chen's, in which he seeks to deepen exchanges and partnerships with local LED firms and solar cell makers such as those based at Nantou's science park. “Local businesses are in need of highly skilled labor, graduates are in need of employment; we are here to create networks,” he explains.
In recent years, NCNU has been an avid participant in several programs supported by the Ministry of Education's Center for University Social Responsibility. These include cross-fertilizing Taiwan's agricultural powerhouse with optoelectronics, and now Nantou’s water bamboo and passion fruits are grown with the aid of LED lights.
Moreover, NCNU researchers are currently identifying the best wavelength, intensity, and duration for specific cultivars based on their innate growth cycle and biological characteristics.
How do a new generation of Taiwanese scholars prepare themselves for this field? To this, Chen replies with the 3 keystones of optoelectronics — light, display, and energy source.
NCNU's curriculum prides itself on providing in-depth understanding of the characteristics of the materials used, as well as the parameters for reading photonic and gaseous levels. This field is a gateway to electrical engineering, chemistry, physics, optoelectronics, and many more fascinating areas of study, so why not take the chance to learn more about semiconductors to broaden one's scientific knowledge and employability?
Professor Chen's rich scientific sensibilities have further cemented the credibility of NCNU's Department of Applied Materials and Optoelectronic Engineering. The reward for developing engaging research projects and experiment-based training? Exceeding recruitment expectations during the time of the coronavirus — full classrooms that the devoted Chen sees as a divine deliverance of grace.
English text by Min Chao