Ultrafast Spectroscopy of III-Nitrides from UV to IR

Professor Alex N. Cartwright,
Department of Electrical Engineering,
Institute for Lasers, Photonics and Biophotonics,
University at Buffalo, Buffalo, NY 14260

ABSTRACT:
There have been a number of technological breakthroughs resulting in successful commercialization of UV and visible LEDs and UV lasers based on III-Nitride materials. However, the development of efficient deep UV laser sources, IR absorbers and visible (green) light emitters requires improving the current understanding of the fundamental optical mechanisms in these materials. The presence of piezoelectric fields, spontaneous polarization and carrier localization complicate the understanding of the optical properties. In this talk, I will present our femtosecond optical studies of InGaN/GaN heterostructures, AlN/GaN heterostructures and InN epilayers used to evaluate material applicability for devices. Specifically, measurements of perpendicular transport and field screening in InGaN/GaN heterostructures, infrared studies of hot carrier relaxation in InN epilayers, and UV spectroscopy of deep UV emitting AlN/GaN materials and the relevance to devices will be presented. Finally, application of InGaN/GaN blue LEDs and LED arrays to biosensors will be presented.

BIO:
Alexander N. Cartwright is an Associate Professor of Electrical Engineering, Director of the Institute for Lasers, Photonics and Biophotonics at the University at Buffalo (UB), and Co-Director of the Electronics Packaging Laboratory at the UB. In 1998, he received a NSF CAREER Award and in 2000 a Department of Defense Young Investigator Award for research on optical properties of III-Nitride materials. More recently, Dr. Cartwright was the recipient of the State University of New York's Chancellor's Award for Excellence in Teaching. Dr. Cartwright's research is focused on III-Nitride materials, quantum dot materials, optical non-destructive testing of stress and strain for device reliability, nanophotonics and nanoelectronics.