Scalable hot carrier array photodetector with absorbing ultra-thin Au film

Near-infrared photodetection is promising for real-time imaging, surveillance, and spectroscopy. We propose an array photodetector using an ultra-thin gold (Au) film on Si, based on hot-carrier injection in a Schottky junction. Au thin films (<5 nm) with a large extinction coefficient enhance hot carrier injection from Au to Si, while thick Au films (>100 nm) primarily reflect light. The device employs thin Au films as active areas and thick ones as electrodes, eliminating the need for insulating materials. Photocurrent properties and operation speed are investigated, showing a rapid response (7.5/8 μs rise/fall time), comparable to commercial Germanium (Ge) photodiodes.