Dr Soh Chew Beng obtained his PhD from the ECE, NUS and has worked as a Scientist in IMRE, A*STAR before joining Singapore Institute of Technology as an Assistant Professor. He has published more than 50 international papers as well as having filed five patents in the area of nitride-based materials. His current research interest is in the area of nitride growth by MOCVD, LEDs for Solid State Lighting as well as characterization and fabrication of nanostructures and devices.
He is an alumnus of the Malik Management School at St. Gallen, Switzerland and joined Heliatek in May 2014 leading the Sales and Product Development department.
Presentation Title
Enhancement in Light Extraction Efficiency from LEDs Grown on Porous GaN Deposited on Patterned Sapphire Substrate
Abstract
GaN and its related group-III nitrides have been investigated intensively for the past two decades they are used for the fabrication of high brightness light emitting diodes (LEDs) in the visible spectrum. The existing commercial GaN LEDs are grown on c-plane sapphire substrates with high density of defects, such as dislocations and stacking faults. These defects cause efficiency reduction and reliability issues of the LEDs. In this work, we propose the reduction of defect densities and generation of a strain-relaxed high crystal quality GaN template using patterned sapphire substrate and porous GaN substrate generated by UV enhanced electrochemical etching. This significantly reduced the defect density of the GaN and enhanced the light extraction efficiency of the LEDs by 50% and 20% over GaN LEDs grown on plane GaN deposited on conventional sapphire substrate and patterned sapphire substrate respectively.