ECpE Seminar with Jing Zhang: III-Nitride Semiconductor Photonics and Nanoelectronics

When

March 13, 2019    
10:00 am - 11:30 am

Where

3043 ECpE Building Addition
Coover Hall, Ames, Iowa, 50011

Event Type

Speaker: Jing Zhang, Kate Gleason Endowed Assistant Professor of Electrical and Microelectronic Engineering at Rochester Institute of Technology

Title: III-Nitride Semiconductor Photonics and Nanoelectronics

Abstract: The emerging of III-Nitride semiconductors has shown promising device applications on photonics and electronics, advancing knowledge in the field of lighting, communication, quantum technologies, health care, and energy. For the pursuit of high efficiency, compact size, and high-level integration, III-Nitride semiconductor technology has been explored extensively in the past decades with significant progress, especially in Nobel-prize winning invention of blue light emitting diodes (LEDs).  In this presentation, I will focus on the use of III-Nitride materials for novel photonic and electronic devices such as ultraviolet (UV) LEDs/ lasers, monolithic white LEDs on novel InGaN template, and nanowire power electronics for switching. For UV photonics, the wide bandgap AlGaN materials have been widely used as the active region. However, the pursuit of efficient UV emitters with wavelength less than 250 nm has been limited to the fundamental challenge on band mixing of the three degeneration valence subbands. Here, I will show the fundamental physics challenge for deep UV LEDs/ lasers including the transverse electric and transverse magnetic polarization switch, as well as the solutions for high-efficiency UV photonics. On the aspect of visible LEDs for solid state lighting, InGaN quantum wells (QWs) on GaN templates are often used as active region for blue or green devices. But such structure suffers from the large internal electrostatic field from the QW strain due to the lattice mismatch between InGaN QW and GaN substrate / barriers. To this end, I will show our solution to the charge separation issue by using novel ternary InGaN substrate for realizing green- and red-emitting QWs with reduced strain and polarization fields. Furthermore, I will discuss about our solution on high-efficiency monolithic white LED based on the thick InGaN template. On the other hand, III-Nitride based LEDs or micro LEDs (mLEDs) have been investigated for the next generation display technology. The persistent issue, however, has been the lack of ability to integrate transistors with LEDs for control. Here, I will present a novel vertical III-Nitride nanowire field effect transistor (FET) that can be monolithically integrated with mLEDs for the first time. The demonstrated voltage-controlled light-emitting unit provides area savings, scaling, and seamless vertical integration. The vertical nanowire FET has great potential in power switching applications too.

Bio: Dr. Jing Zhang is currently the Kate Gleason Endowed Assistant Professor in the Department of Electrical and Microelectronic Engineering at Rochester Institute of Technology. She obtained B.S. degree in Electronic Science and Technology from Huazhong University of Science and Technology (2009), and Ph.D. degree in Electrical Engineering from Lehigh University (2013). Dr. Zhang’s research focuses on developing highly efficient III-Nitride and GaO semiconductor based photonic, optoelectronic, and electronic devices. Her research group is working on the development of novel quantum well active regions and substrates for enabling high-performance ultraviolet and visible LEDs/ lasers, as well as engineering of advanced device concepts for nanoelectronics. Dr. Zhang has published more than 30 refereed journal papers and 65 conference proceedings including invited talks. She is a recipient of Texas Instruments/Douglass Harvey Faculty Development Award, and National Science Foundation (NSF) CAREER Award.

ECpE Seminar Host: Meng Lu

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