Silicon-based high-responsivity GeSn short-wave infrared heterojunction phototransistors with a floating base

We demonstrate silicon-based p-n-p floating-base GeSn heterojunction phototransistors with enhanced optical responsivity for efficient short-wave infrared (SWIR) photodetection. The narrow-bandgap GeSn active layer sandwiched between the p-Ge collector and n-Ge base effectively extends the photodetection range in the SWIR range, and the internal gain amplifies the optical response by a factor of more than three at a low driving voltage of 0.4 V compared to that of a reference GeSn p-i-n photodetector (PD). We anticipate that our findings will be leveraged. to realize complementary metal-oxide-semiconductorcompatible, sensitive, low driving voltage SWIR PDs in a wide range of applications. (C) 2020 Optical Society of America