Design and analysis of a new structure of InAs/GaAs QDIPfor 8-12 μm infrared windows with low dark current

摘要

Based on the effective mass Schrodinger equation and eight-band k.p method, we study optical absorption inthe 8-12 μm infrared window through the conduction subbands of self-assembled InAs/GaAs pyramidalshape quantum dots (QDs) using the finite difference method. Considering homogeneous and inhomogeneousbroadening effects, the absorption spectra of QDs are calculated. Regarding the simulation results, we designa QD infrared photodetector (QDIP) with a double barrier resonant tunnelling (DBRT) at λ = 10 μm. Wecalculate the responsivity, detectivity and dark current for the device, considering the coverage factor of QDs.To enhance the performance of the presented DBRT especially at near room temperature, we propose a modifiedQDIP with asymmetric multiple barrier resonant tunnelling structure. With the modified structure, the darkcurrent reduces to about half an order of magnitude compared with DBRT–QDIP, and detectivity increases to1.4 x 10~9cmHz~(1