Investigation of anodic sulfidizaiton passivation of InAs/GaSb Type-II superlattice infrared detector

The composition of anodic sulfidization layers of GaSb and InAs, prepared by electrochemistry anodic sulfidization, are investigated by X-ray photoelectron spectroscopy (XPS). The result of composition profile of GaSb anodic sulfidization samples, studied by XPS and Ar + etching, indicates that the anodic sulfidization layers contains not only sulfide, but also oxides and oxysulfide. The oxide/oxysulfide is sandwiched by sulfide layer and GaSb. While for the InAs anodic sulfidization sample, the whole anodic sulfidization layer of InAs is composed of oxysulfide and oxide. The oxide is sandwiched by oxysulfide layer and InAs. Moreover, long-wave InAs/GaSb superlattice IR detectors are fabricated to confirm the effect of anodic sulfidization layer on reduction the leakage current. The current–voltage (I-V) result indicates that the dark current of detector with anodic sulfidization layer is more than three orders of magnitude lower than that of without anodic sulfidization layer.