Simulation-based investigation of junction-controlled narrow-band Si photodetector with vertical structure

Abstract

Junction-controlled narrow-band Schottky photodetectors are very attractive in the optoelectronic systems that operate in a small spectral range, due to its high noise immunity, simple structure, and self-powered work mode. In this work, simulation was carried out to study the working mechanism of the junction-controlled narrow-band photodetector based on a vertical silicon Schottky structure. It is showed that the spectral response of the device is mainly dominated by the quasi-neutral region instead of the depletion region of the Schottky structure. Widening quasi-neutral region can obviously red-shift the peak wavelengths of both quasi-neutral region and depletion region, and suppress the device response to short wavelength light. As the doping concentration of the silicon substrate increases, a similar phenomenon can be observed due to the decrease of the diffusion length. Furthermore, increasing surface recombination velocity also can effectively reduce the quantum efficiency of the device at the wavelength <1060 nm. These results signify that junction-controlled narrow-band photodetectors of long-wavelength light can be realized by a variety of simple and feasible methods, indicating their promising application in future photoelectric systems.