UV Wavelength Selective Quaternary GaN-based Sensors

Period of Performance: 09/30/1998 - 09/30/2000


Phase 2 SBIR

Recipient Firm

Witech (widegap Technology)
827 State Street, #15
Santa Barbara, CA 93101
Principal Investigator


Widegap Technology, LLC (WiTech), proposes a Phase II program to develop novel high detectivity GaN-based wavelength-selective photodiodes. Based on the achievements during the BMDO-sponsored Phase I contract (#DASG60-97-M-0145) we will address directly the issues currently limiting device design and performance. Specifically, the proposed program will develop lattice-matched quaternary (A1,In,Ga)N alloy device layers to enable high responsivity, low dark current photodiode fabrication through reduced formation of threading dislocations in the active layer of the device. The resulting detectors will display high detectivity with a peak spectral response which may be tailored in the range from ~235 nm up to 365 nm. This flexibility in design will allow the fabrication of detectors for commercial and military applications including solar-blind operation (sensitivity to wavelengths less than 300 nm), the detection of UVB radiation (280-320 nm) and the detection of biological and chemical agents having key absorption lines in the mid- to deep-UV. The solid-state design of the proposed detectors offer the potential of replacing fragile, bulky, and inefficient photmultiplier tube (PMT) technology. Unlike current solid-state UV sensor technologies such as SiC and Si, nitride based photodectors offer the capability for intrinsic wavelength-selective design without the need for expensive, environmentally sensitive external filtering.