Improved responsivity and detectivity of LPE HgCdTe short-wavelength infrared photodetector by tuning the composition gradient

摘要

This work introduces an effective way to improve the responsivity and detectivity of liquid phase epitaxy (LPE) HgCdTe avalanche focal plane array (FPA) for short-wavelength infrared (SWIR) signal detection by tuning the composition gradient. It is contributed to the Hg-Cd interdiffusion at the HgCdTe/CdZnTe interface during the heat treatment. The Cd composition can be redistributed, which gives different composition (band gap) in the absorption and multiplication regions. The newly designed FPA achieves a 50% improvement in responsivity (gain) and a 30% increase in detectivity over the conventional SWIR FPA (-3 V, 80 K). The newly designed FPA also exhibits a superior performance at 130 K than the conventional FPA at 80 K.