Zinc-hyperdoped silicon photodetectors fabricated by femtosecond laser with sub-bandgap photoresponse

Abstract

Abstract Developing a low-cost, room-temperature operated and complementary metal-oxide-semiconductor (CMOS) compatible near infrared silicon photodetector is of interest for creating all-silicon optoelectronic integrated circuits. However, a silicon-based photodetector usually cannot respond to infrared light with wavelengths longer than 1100 nm, due to the bandgap (1.12 eV) limitation of silicon. Here, we present a zinc-hyperdoped silicon (Si:Zn)-based photodetector that exhibits an enhanced sub-bandgap photoresponse. The Si:Zn shows a broadband infrared absorption over 50%, with a zinc concentration reaches 4.66 × 1019 cm−3 near the surface. The responsivity of the Si:Zn photodetector reaches 0.68 mAW−1 at 1550 nm, −1 V bias, with a rise and fall time of 0.560 ms and 0.445 ms, respectively. The Si:Zn has the potential for a wide range of applications in various fields due to its combination of low cost, CMOS compatibility, and room-temperature operating conditions.