Design Principles for High QE HgCdTe Infrared Photodetectors for eSWIR Applications

In this paper, we study the limiting mechanisms and design criteria of HgCdTe photodetectors for extended shortwave infrared applications with ultra-high quantum efficiency (QE) in both n-on-p and p-on-n technologies. Numerical and analytical models are employed in order to study the possibility of achieving ultra-high QE eSWIR detectors for the operational wavelengths of approximately 2.0 μm, and our study shows that by proper design of absorber layer and doping density, such a detector can be engineered. Furthermore, we demonstrate that the Shockley–Read–Hall (SRH) lifetime, absorber layer doping density and absorber layer thickness all have an impact on the quantum efficiency whether the detector is used as a small-area pixel element in a focal plane array or as a discrete large-area detector for sensing applications.