Influence of interdiffusion on strained GaInSb/InAs material and its application on long-wavelength infrared photodectors

摘要

Abstract: Intermixing effect in type-II Ga$-0.6$/In$-0.4$/Sb/InAssuperlattices is studied. The interdiffusion of bothgroup-III and group V atoms across the heterointerfacemodifies the superlattices optical properties andelectronic structures. The intermixed-induced strainhas different effects on the band structure of therespective strained layers. Conduction band isundergone successive changes where the barrier heightwas initially increased in potential and subsequentlybecame lower than the as-grown one for increasingextent of intermixing. Consequently the confinementprofile is tuned from an abrupt interface to a gradedshape. Intersubband transition is investigated in theintermixed superlattices where the absorption peakwavelength is red shifted continuously from the asgrown 11.7 to the interdiffused 12.5 $mu@m. Both theintermixed absorption and responsivity are reducing inmagnitude. However, dark current is reduced at initialstage of intermixing as a result of the increase inconfinement potential and the effective barrier width.Detectivity at 77 K is enhanced for the intermixeddetector from 2.5 $MUL 10$+11$/ to 3 $MUL 10$+11$/cm$ROOT@Hz/W, which is comparable to the MCTdetector.!23