Optoelectronic properties analysis in InAs/GaSb type-II superlattices long-wave infrared detectors based on graded barrier structure

Advances in bandgap engineering of various III-V compound semiconductors have led to innovative infrared detector architectures such as InAs/GaSb barrier-type structures. This barrier-type structure detectors are characterized by enhanced carrier transport optimization, a significant reduction in interface state density, and superior thermal stability, alongside a notable reduction in dark current and noise levels. These improvements not only substantially enhance the fundamental electrical characteristics of semiconductor devices but also expand their application flexibility and environmental adaptability through meticulous bandgap engineering. This article reports a study on optoelectronic properties based on a graded barrier InAs/GaSb T2SLs long-wave infrared detector for the first time, with detailed analysis from two aspects: electrical and optical properties. The surface leakage current is measured through variable area testing. The study correlates effective bandgap and activation energy across temperatures, providing insights into bulk dark current components. In addition, the temperature dependence of blackbody responsivity is also analyzed.