New Sensing Capabilities: GaN Based Dualband UV-IR Detectors

The proposed innovation is the development of a novel dual band detector responding in both the UV and IR regions, based on a GaN/AlGaN heterostructure. The IR response is based on HEterojunction Interfacial Workfunction Internal Photoemission (HEIWIP) detectors, which was demonstrated using AlGaAs/GaAs and GaN/AlGaN structures. By also using interband transitions, response in the UV range at room temperature was incorporated into the device during Phase I. A device with responses in the UV shorter than 350 nm and in the 5-13 micron range (at 80K) was demonstrated. By varying the material composition the spectral ranges can be tailored for the specific application. The detector would allow simultaneous imaging of both spectral ranges using a single detector array. This would provide a large advantage over current approaches which use separate detectors to image the two regions. By varying the Al fraction in the AlGaN, the detector can be easily extended to cover the range up to 40 microns. During Phase II, work will concentrate on optimization for specific applications and development of methods for distinguishing the IR and UV responses in a single pixel. Incorporating InGaN once could even extend the coverage in to the visible region to have a detector covering UV- Vis-IR.