  Polycrystalline PbSe for mid-wave IR (MWIR) photodetector is an attractive
material option due to high operating/ambient temperature operation and
relatively easy and cheap fabrication process, making it candidate for
low-power and small footprint applications such as internet-of-thing (IoT)
sensors and deployment on mobile platforms due to reduced/removed active
cooling requirements. However, there are many material challenges that reduce
the detectivity of these detectors. In this work, we demonstrate that it is
possible to improve upon this metric by externally modulating the lifetime of
conducting carriers by application of a back-gate voltage that can control the
recombination rate of generated carrier. We first describe the physics of
$PbSe$ detectors, the mechanisms underlying carrier transport, and long
observed lifetimes of conducting carriers. We then discuss the voltage control
of these inverted channels using a back-plane gate resulting in modulation of
the lifetime of these carriers. This voltage control represents and extrinsic
"knob" through which it may be possible to open a pathway for design of high
performance IR photodetectors, as shown in this work.
