Short-wavelength infrared InAs/GaSb superlattice hole avalanche photodiode**Project supported by the National Natural Science Foundation of China (Grant Nos. 61874179, 61804161, and 61975121) and the National Key Research and Development Program of China (Grant No. 2019YFB2203400).

Abstract

We demonstrate two short-wavelength infrared avalanche photodiodes based on InAs/GaSb superlattice grown by metal-organic chemical vapor deposition. The difference between the two devices, namely, p+n−n+ and p+nn−n+, is that the p+nn−n+ device possesses an additional middle-doped layer to separate the multiplication region from the absorption region. By properly controlling the electric field distribution in the p+nn−n+ device, an electric field of 906 kV/cm has been achieved, which is 2.6 times higher than that in the p+n−n+ device. At a reverse bias of –0.1 V at 77 K, both devices show a 100% cut-off wavelength of 2.25 μm. The p+n−n+ and p+nn−n+ show a dark current density of 1.5 × 10−7 A/cm2 and 1.8 × 10−8 A/cm2, and a peak responsivity about 0.35 A/W and 0.40 A/W at 1.5 μm, respectively. A maximum multiplication gain of 55 is achieved in the p+nn−n+ device while the value is only less than 2 in the p+n−n+ device. Exponential nature of the gain characteristic as a function of reverse bias confirms a single carrier hole dominated impact ionization.