Srabanti Chowdhury, Professor, Department of Electrical and Computer Engineering, University of California, Davis

Prof. Chowdhury’s group focuses on materials and device research for RF and Power electronics. Her academic career was launched at UCSB developing Vertcial GaN-based transistors. Vertical GaN technology has matured substantially over the last decade and she continues to contribute to the field by developing novel power switching devices. Her work on RF electronics started with her DARPA young faculty award where she is developing high Watts-per-mm devices. Besides GaN, her group works extensively on Diamond material and device development for high temperature electronics. She has received the NSF CAREER, AFOSR Young Investigator Program (YIP) and DARPA Young Faculty Award (YFA) in 2015. She received the Young Scientist Award at the International Symposium on Compound Semiconductor (ISCS) in 2016 for her contribution towards GaN-Vertical device development.

Role of Wide Bandgap Semiconductors in Next-Generation Power Converters

Wide bandgap semiconductors present a pathway to push the limits of power conversion efficiency beyond that available from Silicon-based devices, enabling significant energy savings. Recent progress in Gallium Nitride (GaN)-based power electronic devices has been compelling. Reducing conversion losses is not only critical for minimizing consumption of limited resources, it simultaneously enables new compact architectures, the basis for a new industry offering increased power conversion performance at reduced system cost. This is because GaN devices enable power electronics with 1) higher efficiency at higher frequency of operation and 2) higher efficiency over a wider range of operating temperature, compared with what is possible with Si, which is approaching its physical material limit in power conversion. High efficiency operation at higher operating frequency reduces the size, weight and cost of the overall system by reducing the size of the passive components and the heat sink. GaN-based Photovoltaic (PV) inverters have achieved efficiency above 98% at a pulse-width modulation frequency of 50 kHz (vs. 96% with Si at 15 kHz), reducing loss by 50%, thereby shrinking the PV inverter size by 40%. While Lateral GaN devices are more matured in technology and have entered the medium power conversion market (up to 10 kW), Vertical GaN devices are evolving to address high power conversion (10 kW-10 MW). The novelty of the device design can be extended beyond GaN to other wider bandgap materials like Gallium Oxide, Aluminum Nitride and Diamond for more futuristic power and other novel fields like photovoltaic and GHz-THz frequency applications.