One-dimensional analysis of N-on-p Pb1−xSnxSe compositionally graded heterojunction photodetectors

Abstract

This work presents a theoretical investigation of the performance of N-on-p Pb1−xSnxSe heterojunction photodiodes with a linear gradient in composition. We quantify the improvement of the quantum efficiency, R0A product, and detectivity for a graded heterojunction device as compared to a basic p-n homojunction photodetector. In addition to enhanced overall device performance, the graded heterojunction diode exhibits considerable improvements when surface recombination velocities are taken into account. For low surface recombination velocities the detectivity of the graded N-on-p heterostructure increases nearly two-fold in comparison to the p-n homojunction, while for high surface recombination velocities the detectivity of the graded heterostructure increases by as much as an order of magnitude.

Dielectric Charge Screening of Dislocations and Ionized Impurities in PbSe and MCT

“…1 Presently, Pb 1-x Sn x Se detectors are Schottky-induced p-n junctions; therefore achieving an in situ-grown p-n junction is a significant feat, as these devices have the potential to compete with presently available technology. 2 As a consequence, we expect a resurgence of these materials. Therefore, there is an increased need for an in-depth theoretical understanding of these material systems and devices particularly in regards to the relationship between material defects and device performance.…”

“…[8][9][10] Here we concentrate on continued improvements of Pb 1-x Sn x Se material quality and device design along with novel p-n junction growth techniques which are expected to greatly improve the performance of IV-VI mid-IR detectors and focal-plane arrays. 2 In this work, we calculate the shielding effects of the dielectric constant by taking into account the scattering of electrons due to ionized impurities and small charged dislocations, as discussed in the following section. The Coulomb field of ionized impurities or charged dislocations retards the motion of electrons, leading to an energy loss in motion.…”