Evidence for a defect level above the conduction band edge of InAs/InAsSb type-II superlattices for applications in efficient infrared photodetectors

作者：A. D. Prins, Michael K. Lewis, Zoe L. Bushell, Stephen J. Sweeney, S. Liu, Y.–H. Zhang · 发表于：Applied Physics Letters · 年份：2015 · DOI：10.1063/1.4919549 · 被引用次数：34 · 研究领域：Advanced Semiconductor Detectors and Materials、Semiconductor Quantum Structures and Devices、Chalcogenide Semiconductor Thin Films

We report pressure-dependent photoluminescence (PL) experiments under hydrostatic pressures up to 2.16 GPa on a mid-wave infrared InAs/InAs0.86Sb0.14 type-II superlattice (T2SL) structure at different pump laser excitation powers and sample temperatures. The pressure coefficient of the T2SL transition was found to be 93 ± 2 meV·GPa−1. The integrated PL intensity increases with pressure up to 1.9 GPa then quenches rapidly indicating a pressure induced level crossing with the conduction band states at ∼2 GPa. Analysis of the PL intensity as a function of excitation power at 0, 0.42, 1.87, and 2.16 GPa shows a clear change in the dominant photo-generated carrier recombination mechanism from radiative to defect related. From these data, evidence for a defect level situated at 0.18 ± 0.01 eV above the conduction band edge of InAs at ambient pressure is presented. This assumes a pressure-dependent energy shift of −11 meV·GPa−1 for the valence band edge and that the defect level is insensitive to pressure, both of which are supported by an Arrhenius activation energy analysis.