InGaAs nBn SWIR detector design with lattice-matched InAlGaAs barrier

Abstract

Dark current optimization with band gap engineering has been numerically studied for InGaAs nBn typeinfrared photodetectors. Undoped InAlGaAs grading layers are utilized in constructing the barrier and dipole deltadoped layers are placed in both sides of the graded layers for eliminating valence band offset. As a result, the high bandgap barrier layer blocks the majority carriers and allows minority carrier flow while minimizing various dark currentcomponents, as expected from an nBn detector. Substantial improvement has been shown in the dark current levelwithout compromising any photoresponse compared to the conventional pn junction and recently proposed all InGaAsnBn type photodetectors.