Coupling efficiency of infrared radiation to electron intersubband transition in quantum well infrared photodetector by a two-dimensional (2D) grooved grating is examined. A resonant enhancement of the coupling efficiency at a certain optimal groove depth is predicted and confirmed experimentally. It is argued that a detector with a properly designed ordered cross grating performs better than a detector with optimized 2D random grating. In a detector with ordered grating a quantum efficiency of 75% is obtained with a doping level of only in each quantum well and dark current density of 0.34 mA/cm2 at 78 K.
Optimized random/ordered grating for an n-type quantum well infrared photodetector
Shmuel I. Borenstain, U. Arad, I. Lyubina, A. Segal, Y. Warschawer; Optimized random/ordered grating for an n-type quantum well infrared photodetector. Appl. Phys. Lett. 25 October 1999; 75 (17): 2659–2661. https://doi.org/10.1063/1.125110
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