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 have been demonstrated using AlGaAs/GaAs structures. By also using interband transitions, response in the UV range can be incorporated into the device. A GaAs detector structure was shown to respond in both the NIR and FIR regions demonstrating the dual band capability. A material system change to GaN/AlGaN is expected to shift the NIR response into the UV range providing a UV-IR dual band detector. By varying the material compostion the spectral ranges can be tailored for the specific application. The initial detectors will operate in the 0.2 - 0.35 micron UV range and 8--14 micron IR range. The proposed 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.