Minority carrier lifetime and operating voltage dependence on the barrier layer thickness in nBn infrared photodetectors

XBn InAs/InAsSb architectures are now a standard to design high performance mid-wave infrared photodetectors with increased operating temperatures. In this paper, the influence of barrier layer ( BL ) thickness on the electrical and electro-optical characteristics of such detectors is investigated. The study shows that this parameter has a key role on turn-on voltage and carrier lifetimes. A model is derived to analyze the dependence of this voltage on BL thickness and doping conditions. It is found that an optimum thickness comprised between 100 and 140 nm can minimize it. Additionally, a decrease in the lifetimes of minority carriers is observed as the BL thickness is increased. This behavior is studied as a function of temperature and applied bias voltage .