Theoretical design of uncooled middle infrared PbSe P+pBn+ barrier detectors

A novel uncooled mid-wavelength infrared (MWIR) P⁺pBn⁺ barrier detector based on epitaxial PbSe absorber layer on Ge substrate is theoretically investigated by finite element analysis in order to achieve optimal detection performance. The simulated results show that the P⁺pBn⁺ barrier architecture can further effectively reduce the room-temperature dark current to 4.45 mA cm⁻² under −0.1 V bias, which is 12 times lower than a PbSe pBn⁺ unipolar barrier device in a previous study. Moreover, the P⁺pBn⁺ barrier architecture exhibits excellent responsivity and detectivity of 1.83 A W ⁻¹ and 3.23 × 10¹⁰ cm Hz^1/2 W⁻¹ at 3.8 μm, respectively. These results suggest that this P⁺pBn⁺ barrier detector based on natural MBE epitaxy technology could have potential in the emerging high-sensitivity and high-detectivity uncooled MWIR applications.