A Universal Approach to Enhancing Silicon Hot-Carrier Photodetectors for CMOS-Compatible SWIR Imaging

Silicon hot-carrier photodetectors offer a CMOS-compatible pathway for short-wavelength infrared (SWIR) detection, yet their practical deployment in imaging systems has been constrained by intrinsically low quantum efficiency. Here, we present a universal approach to enhance the quantum efficiency of silicon hot-carrier photodetectors through the use of a quasi-generalized antireflection coating (QARC). The QARC design enhances optical absorption by several-fold in ultrathin metal electrodes that form the metal-silicon Schottky junction, without degrading carrier injection, and is effective regardless of the metal type or electrode thickness. Consequently, a QARC-integrated hot-carrier photodetector achieves a responsivity of 7.8 mA/W and an external quantum efficiency of 0.82% at 1310 nm-nearly doubling that of devices without QARC-while maintaining comparable dark current and microsecond-scale temporal response, as demonstrated using an ultrathin copper electrode. This enhanced quantum efficiency enables the first demonstration of SWIR imaging using a CMOS-compatible silicon hot-carrier photodetector, offering higher signal levels and sharper features under low illumination. The silicon hot-carrier photodetector with QARC offers a promising route toward practical, CMOS-compatible SWIR imaging sensors.