Carrier concentration and in-plane mobility in both non-intentionally and Si-doped InAsSb and InAs/InAsSb type-II superlattice materials for space-based infrared detectors

The sensitivity of III-V-based infrared detectors is critically dependent upon the carrier concentration and mobility of the absorber layer, and thus, accurate knowledge of each is required to design structures for maximum detector performance. Here, measurements of the bulk in-plane resistivity, in-plane mobility, and carrier concentration as a function of temperature are reported for non-intentionally doped and Si-doped mid-wave infrared InAs₀.₉₁Sb₀.₀₉ alloy and InAs/InAs₀.₆₅Sb₀.₃₅ type-II superlattice materials grown on GaSb substrates. Standard temperature- and magnetic-field-dependent resistivity and the Hall measurements on mesa samples in the van der Pauw configuration are performed, and multicarrier fitting and modelling are used to isolate transport of each carrier species. The results show that up to 5 carrier species of the surface, interface and bulk variety contribute to conduction, with bulk electron and hole mobility up to 2·10⁵ cm²/V s and 8·10³ cm²/V s, respectively and background dopant concentration levels were between 10¹⁴ and 10¹⁵ cm¯³. The in-plane mobility temperatures dependence is determined and trends of each carrier species with temperature and dose are analysed.