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

ABSTRACT 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.