High Detectivity Tunable Mid-Wave Infrared Detector Array Using Wafer-Bonded Gallium Antimonide/Gallium Arsenide Detector Technology

This work will develop a tunable focal plane array of Gallium Antimonde (GaSb) based resonant cavity infrared detectors (RCIDs) with detectivity D* competitive with established HgCdTe detectors and capable of tuning over 500nm in the 3-5 micron range. The RCID approach enables use of a thin absorber with low dark current and multi-pass absorption for high quantum efficiency. This work will employ wafer bonding to combine GaSb- based absorber regions with GaAs- based mirrors to create a scalable and manufacturable design. Phase I work will proceed through the following 3 objectives: 1. Design RCID structure capable of 500nm tuning range and D*>4X1011 cm-Hz1/2/Watt at 200K. 2. Fabricate/test fixed wavelength version of tunable RCID designed under objective 1. 3. (Phase I Option): Demonstrate tunability of a single-element consistent with theory. Efforts under objective 1 will explore different mirror options, and tunable absorption curves for various designs and arrive at an optimum design for fabrication. Objective 2 will focus on fabrication of a fixed wavelength version of the design developed under objective 1, including wafer bonding, dry etching, sidewall passivation, metallization, and dark current/resonance testing. In objective 3 under the phase I option, Praevium will demonstrate tuning of a single detector element.