Visible-blind short-wavelength infrared photodetector with high responsivity based on hyperdoped silicon

Developing a low-cost, room-temperature operated and complementary metal-oxide-semiconductor (CMOS) compatible visible-blind short-wavelength infrared (SWIR) silicon photodetector is of interest for security, telecommunications, and environmental sensing. Here, we present a silver-supersaturated silicon (Si:Ag)-based photodetector that exhibits a visible-blind and highly enhanced sub-bandgap photoresponse. The visible-blind response is caused by the strong surface-recombination-induced quenching of charge collection for short-wavelength excitation, and the enhanced sub-bandgap response is attributed to the deep-level electrontraps- induced band-bending and two-stage carrier excitation. The responsivity of the Si:Ag photodetector reaches 504 mA.W-1 at 1310 nm and 65 mA.W-1 at 1550 nm under -3 V bias, which stands on the stage as the highest level in the hyperdoped silicon devices previously reported. The high performance and mechanism understanding clearly demonstrate that the hyperdoped silicon shows great potential for use in optical interconnect and power-monitoring applications. (C) 2019 Chinese Laser Press