Demonstration of a Dual-Band InAs/GaSb Type-II Superlattice Infrared Detector Based on a Single Heterojunction Diode

摘要

We propose and demonstrate a new single heterojunction structure for dual-band detection based on typeII InAs/GaSb superlattices grown by metal-organic chemical vapor deposition. The structure simply consists of a p-type mid-wavelength contact layer, an n-type mid-wavelength absorber and an n-type long-wavelength absorber. At a small reverse bias, the presence of a potential barrier in the valence band between the two adjacent absorbers allows the mid-wavelength channel to work only; at a higher bias where the potential barrier no longer exists, photo-generated holes in the long-wavelength absorber are able to transport through the mid-wavelength absorber and reach the p-contact, making both channels to work. At -0.1 V and 77 K, the mid-wavelength channel exhibited a 50% cut-off wavelength of 3.5 mu m, a dark current density of 2.4x10(-9) A/cm(2), and a peak specific detectivity of 1.4x10(13) cm.Hz(1/2) /W; while at -0.3 V the long-wavelength channel exhibited a 50% cut-off wavelength of 8.0 mu m, a dark current density of 5.1x10(-7) A/cm(2), and a peak specific detectivity of 3.6x10(12) cm.Hz(1/2) /W.