Physical modeling and uncertainty quantification of dark current in InAs/GaAs QDIPs with AlGaAs current blocking layers

Abstract

The dark current remains the primary limiting factor in the performance of Quantum Dot Infrared Photodetectors (QDIPs), particularly for operation at elevated temperatures. In this work, we present a comprehensive physical model for the dark current transport in InAs/GaAs QDIPs incorporating an Al_0.3Ga_0.7As current blocking layer. The model integrates the emission-capture framework with a rigorous WKB approximation for field-assisted tunneling in spherical quantum dot geometry. We validate the analytical formulation against experimental data at room temperature ($T=290$ K), achieving excellent agreement with a logarithmic root-mean-square error of 0.217. A comparative architectural analysis reveals that the inclusion of the heterointerface blocking layer suppresses the dark current by approximately six orders of magnitude compared to standard designs, providing a quantitative theoretical basis for the device’s room-temperature functionality. Furthermore, we perform a Monte Carlo uncertainty quantification to assess manufacturing tolerances, demonstrating that the device performance is robust against quantum dot size fluctuations but highly sensitive to barrier composition variations. These findings establish design guidelines for optimizing high-temperature infrared sensors, predicting a detectivity enhancement of three orders of magnitude with moderate cooling to 200 K.