Prof. Shengjun Zhou
Wuhan University, China
Title: High-brightness GaN-based visible and ultraviolet light-emitting diodes
Abstract:
GaN-based
light-emitting diodes (LEDs) have been applied in many areas, such as
backlights for liquid crystal displays (LCDs), solid-state lighting, visible
light communications, head-up displays, and optogenetics. The internal quantum
efficiency of GaN-based blue LEDs has been above 85%. However, the light
extraction efficiency of GaN-based blue LEDs is relatively low due to total
internal reflection (TIR) of the generated light at the GaN/air interface
resulting from their very different refractive indices. This talk will outline
the emerging challenges in design and fabrication of light extraction micro/nao-structure
for high efficiency LEDs. Research in developing efficient light extraction micro/nao-structures,
such as surface roughening, patterned indium-tin oxide (ITO) transparent conductive
layer, patterned SiO2 current blocking layer, cone-shaped patterned
sapphire substrate, wavy sidewalls, sidewall nano-prisms, embedded air void
microstructure, distributed Bragg reflector (DBR), laser lift-off, nanoscale
Ni/Au wire gird, and flip-chip
technology, will
be discussed. In
addition, the recent development in green LEDs and ultraviolet LEDs will also
be discussed in this talk.
Biography:
Shengjun Zhou received the Ph.D. degree from Shanghai Jiao Tong University, Shanghai, China, in 2011. He is now a Professor at Wuhan University. His current research interests lie in the areas of GaN-based blue/green/ultraviolet LEDs, nitride semiconductors, nanoimprint lithography and direct laser writing with applications in electronic and photonic devices. He is well known as an industrial technologist. Prior to joining Wuhan University, he was a CTO at Quantum Wafer Inc. from 2011 to 2014, focusing on the development of high-brightness GaN-based high-power LEDs. He was a research fellow at University of Michigan, Ann Arbor, from 2014 to 2015. He received many academic awards including distinguished Young Scholar of Hubei province, Chutian Scholar of Hubei province, and Luojia Young Scholar of Wuhan University. He has published more than 50 papers and holds 10 patents.