Sanjay Krishna's Research Group at CHTM

Technical Overview. In this project, we are investigating the performance of normal incidence LWIR (8-12 um) detectors based on intersubband transitions in DWELLs. The detectors are designed, grown, fabricated and characterized in our research group. In the past few years, we have demonstrated (i) control of the operating wavelength of the detector through heterostructure engineering resulting in a LWIR atmospheric window detector, (ii) VLWIR ( 23 um) response at 77K (highest operating temperature for any intersubband detector) and (iii) a three color (MWIR, LWIR and VLWIR) detector and (iv) the first long wave infrared quantum dot focal plane array based on a 320x256 ROIC (in collaboration with Industrial partners). In collaboration with Prof. Hayat and Prof. Tyo, we have also realized a smart DWELL detector whose peak operating wavelength and spectral bandwidth can be tuned by changing the operating bias. We are presently setting up a Midinfrared Imaging Characterization and Applications (MICA) laboratory to test FPAs.

Funding for this research has been provided by:
• Air Force Research Laboratory
• Sandia University Research Grant
• National Reconnaissance Organization
• National Science Foundation
• Director of Central Intelligence Program

Current Personnel: Prof. Andreas Stintz, Ram Saran Attaluri, Kalyan Teja Posani, Jiayi Shao, Eric Varley and Michael Lenz.

Collaborators: Profs. Hayat and Tyo (UNM, ECE); S.W. Kennerly and J.W. Little (ARL); Dr. D. Cardimona (AFRL); Dr. J. Simmons (SNL); Prof. U. Perera (GSU); Prof. O. J. Painter (Caltech); Dr. J. McAdoo (ITT Industries); Dr. Chris Dries (Sensors Unlimited Inc); Dan Carothers (BAE systems).

Selected Publications.
• S.Krishna, D. Forman, S. Annamalai, P. Dowd, P. Varangis, T. Tumolillo, A. Gray, J.Zilko, K. Sun, M. Liu, J. Campbell, D. Carothers “Demonstration of a 320 x 256 Two-Color Focal Plane Array Using InAs/InGaAs Quantum Dots in a Well Detectors”Appl. Phys. Lett, 86, 193501, 2005.