Publication Date:
2015-04-29
Description:
Mid-wave infrared, nBn detectors remain limited by diffusion current generated in the absorber region even when defect concentrations are elevated. In contrast, defect-limited conventional pn-junction based photodiodes are subject to Shockley-Read-Hall generation in the depletion region and subsequent carrier drift. Ideal nBn-architecture devices would be limited by Auger 1 generation; however, typical nBn detectors exhibit defect-dominated performance associated with Shockley-Read-Hall generation in the quasi-neutral absorbing region. Reverse saturation current density characteristics for defect-limited devices depend on the minority carrier diffusion length, absorbing layer thickness, and the dominant minority carrier generation mechanism. Unlike pn-based photodiodes, changes in nBn dark current due to elevated defect concentrations do not manifest at small biases, thus, the zero bias resistance area product, R o A, is not a useful parameter for characterizing nBn-architecture photodetector performance.
Print ISSN:
0003-6951
Electronic ISSN:
1077-3118
Topics:
Physics
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