Simulation and Optimization of Heterojunction Photodetectors Based on Mercury Cadmium Telluride

In the present paper, the performance of n-on-p heterojunction photodetector based on Hg 1-x Cd X Te (MCT) has been analyzed theoretically for operation at 4.2 μm. The energy band diagram, electric field profile, carrier concentration, dark current, dynamic resistance, quantum efficiency and detectivity have been calculated and optimized as a function of different variables such as device thickness, reverse voltage and operating wavelength to optimize the performance of p-n heterojunction photodetector at room temperature. The dependence of the p-n junction position within heterostructure on the bandgap energy profiles and the influence of doping concentration on photodetector parameter have been studied. The dark current-voltage characteristics and dynamic resistance versus voltage characteristics has been simulated. The optical characterization takes into account the quantum efficiency and detectivity of the heterojunction photodetector. Results of our simulated study reveal that under suitable biasing condition, the photodetector offers a dark current, I D ≈10 -11 A, a zero-bias resistance, R≈1.32 x 10 7 Ω, quantum efficiency η ≈ 74% and detectivity D* ≈ 8.3 x 10 10 mHz 1/2 /W.