Director of CHTM
Degrees: PhD University of Michigan at Ann Arbor, 2001 MS Electrical Engineering, University of Michigan at Ann Arbor,1999 MSc Physics, Indian Institute of Technology, Madras, 1996 BSc (Hons) Physics, SSSIHL, Bangalore, India, 1994
Sanjay Krishna’s group proposed and pioneered the quantum dots in a well heterostructures (DWELL) for detectors in May 2002. The DWELL design combined the advantages of quantum well infrared photodetectors (QWIPs) such as a “dial in recipe” for a desired operating wavelength with the unique properties of quantum dot infrared photodetectors (QDIPs) such as low dark current and normal incidence operation. In addition, the DWELL design could exploit quantum confined Stark Effect (QCSE) due to the asymmetry of the potential, leading to the development of a “smart” focal plane array whose spectral response could be controlled using an external bias. A U.S. patent (Krishna et al. #7,217,951) was awarded for this work. In the past few years, research groups around the world have investigated the DWELL design for intersubband detectors. This includes researchers at JPL, Northwestern University, Sheffield University Australian National University, University of Massachusetts and Mc- Master University. Recently, the DWELL detectors were successfully transitioned to NASA-JPL, where the demonstration of the largest QD based imager using a 640x512 focal plane array was undertaken. Although there is a fair amount of research to be done to reduce the dark current and increase the operating temperature of QD based devices, the DWELL design is a promising approach to realize next generation infrared imagers. Dr. Krishna is co-founder of ECE’s Expand Your Engineering Skills (EYES) program, which brings high-caliber international students to ECE for summer research under the guidance of a faculty advisor (see page 29). He is the recipient of the Gold Medal from IIT and an IEEE Outstanding Engineer Award.