Electron Transport in InAsSb-Based nBn Photodetector Structures

Magnetic-field-dependent Hall-effect measurements and high-resolution mobility spectrum analysis have been employed to determine electronic transport parameters in InAsSb-based nBn structures. Three samples were studied, with nominally identical epitaxial layer structure but with barrier layers of different compositions. Two separate well-defined electron species, associated with the two distinct doping regions, were identified. The extracted electron concentrations were found to be in excellent agreement with the nominal doping density of the absorber and the back contact layers for all samples studied. For all samples, electron mobility appears to be limited by impurity scattering, whereas the relatively small differences in extracted mobility values between samples are likely to be due to unintentional variations in ionized impurity and/or defect concentration in the samples.