Dr. Zhen-Yu Li / 李鎮宇 博士
Project Director
R & D Div.(I)
EPISTAR-HUGA OPTOTECH INC.• Researcher, Academia Sinica, Taiwan
• Principal Engineer/Project Manager, TSMC Solid State Lighting, Taiwan
• Visiting Scholar, Nagoya University, Japan
• Postdoctoral Research Fellows, NCTU, Taiwan
Zhen-Yu Li received the B.S. degree in Department of Electronic Engineering from Chung Yuan Christian University, Taiwan, R.O.C., in 2003, and the Ph.D. degree in Engineering from Chung Yuan Christian University, Taiwan, R.O.C., in 2007.
He has an extensive professional career both in research and industrial research institutions that includes: a senior Research Assistant in Institute of Nuclear Energy Research Atomic Energy Council, Executive Yuan (2003–2007); and a Postdoctoral Research Fellow in Department of Photonics & Institute of Electro-Optical Engineering at National Chiao Tung University (2007–2011); and a Principal Engineer for Epi Technology Development and reliability assessment in TSMC Solid State Lighting, Ltd (20011–2014); and a senior Postdoctoral Research Fellow in Academia Sinica (2014-current).
He has over 11 years of research experience on III–V and III-nitride compound semiconductors, material characterization, optoelectronic devices, and hetero-epitaxial techniques consisting of liquid-phase epitaxy (LPE) and metal-organic chemical vapor deposition (MOCVD). In 2006, He is the first one to successfully grow GaAs epilayer on Si substrate with a record low EDP of ~105 cm-2 by using a-GaAs/a-Si double amorphous buffer layers (a-GaAs/a-Si DABL) and thermal cycle annealing (TCA).
In the meantime, he also applied this a-GaAs/a-Si DABL and TCA to demonstrate over 19% conversion efficiency for GaAs on Si single-junction solar cell. From 2007 to 2011, he has successfully grown crack-free AlN/GaN DBR with a reflectivity of 99.4%. He also applied this DBR to demonstrate world’s first CW and RT electrically pumped GaN-based VCSELs. Following, he has developed a novel nano-scaled epitaxial lateral overgrowth (NELOG) technique of GaN on a SiO2 nanorod-array patterned sapphire substrate to enhance the quality and efficiency of GaN-based LEDs on sapphire, and he has transferred this NELOG technique to Epistar for production. He has designed a graded-composition electron blocking layer (GEBL) with Al composition increasing along the [0001] direction for reducing nitride LED efficiency droop, and he has transferred this GEBL technique to Epistar for production. He has demonstrated over 110 lm/W (120 lm) GaN-based LEDs on 6-inch Si substrate by introducing a composite buffer layer structure and quaternary superlattices electron-blocking layers.
In 2014, he proposed a new method that is carbon-doped AlN/GaN superlattices structure to improve the breakdown voltage (BV) of GaN HEMTs on Si substrate, yielding a record high BV of over 1854V. He had authored and coauthored 50 internal journal papers, 2 invited book (“Heteroepitaxial Growth of III-Vs Epilayer on Si Substrate by AP-MOCVD” and “Chapter 7 Nanostructured LEDs in the Book: Nitride semiconductor light- emitting diodes (LEDs)”), and 25 patents.