Design of uncooled mid-wave infrared detectors based on lead selenide barrier structure

Abstract

Mid- and long-wavelength infrared (IR) photodetectors incorporating narrow-bandgap semiconductors often face the challenge of large room-temperature dark current, limiting their applications in military and civilian. Herein, a novel pBn+ barrier detector architecture based on lead selenide/indium selenide barrier structure is proposed to significantly suppress the dark current, so that uncooled mid-wave IR (MWIR) photodetectors with high performance can be achieved. The finite element analysis of the detector demonstrates reduced room-temperature dark current down to 55 mA/cm2 under -0.1 V bias, which is a two-fold decrease compared to InAs/InAsAb type-II superlattice detector. In addition, at room temperature, the optimized pBn+ barrier detector exhibits excellent responsivity and detectivity of 1.23 A/W and 9.47×109 cm·Hz1/2·W-1 at 3.8 μm, respectively. The PbSe-based barrier architecture provides a promising industrialization solution for high-performance uncooled MWIR photodetectors.

Theoretical design of uncooled mid-infrared PbSe P+pBn+ barrier detectors

“…In addition, compared to uncooled HOT photodetectors, fabricated III-V material (T2SLs, InAsSb) and other PbSe device structures, the PbSe P + pBn + device is more advant ageous and exhibits superior performance highlighted by its low dark current and high detectivity, as shown in figure 9 and supplementary material table S1 [22,55,[58][59][60][61][62]. Furthermore, higher detectivity can be expected by further suppressing the dark current and increasing the quantum efficiency by further optimizing the P + pBn + device design and growth technology of materials, such as decreasing the doping concentration of PbSe absorber [41].…”

“…Recently, Qiu et al first proposed an uncooled pBn + BIRD architecture based on PbSe absorber layer, and demonstrated theoretically that the room-temperature dark current of the pBn + structure is three times lower than that of the traditional PbSe pn homojunction device [41]. Using PbSe and InSe 2D materials has been the first attempt to construct a PbSe pBn + van der Waals heterostructure unipolar barrier detector with ultrafast speed and high responsivity, where lattice mismatch and interface defects are avoided.…”