Electronic transport in InAs/GaSb type-II superlattices for long wavelength infrared focal plane array applications

Abstract

Electronic transport parameters in a nominally P+/π/P+ InAs/GaSb type-II superlattice vertical photoconductor structure for long-wavelength infrared detectors have been characterized employing magnetic field dependent resistivity and Hall-effect measurements, and high-resolution mobility spectrum analysis. Carrier transport parameters from both the P+ and nominally π regions were obtained over the 80 to 300K temperature range. At 300 K, the minority carrier electrons in the nominally π region was found to be characterized by a mobility and concentration of 11,000 cm²/Vs and 1.1×10¹⁷ cm^-3, respectively. Taking into account our previously reported room-temperature vertical electron transport parameters,¹ the vertical to lateral mobility and carrier concentration ratios have been determined to be 0.19 and 5.5×10^-4 , respectively. A miniband energy gap of 192±8 meV was estimated from the thermal activation of the minority carrier electrons in the lightly doped InAs/GaSb superlattice region.