Self-powered silicon metal–semiconductor–metal photodetector based on asymmetric Schottky barrier heights

Abstract

We present a highly efficient self-powered silicon metal–semiconductor–metal (MSM) photodetector (PD). The key feature of our device lies in its asymmetric electrode design, which induces an asymmetry in the Schottky barrier heights at the MSM interface. We utilize a built-in electric field that originates from the larger electrode and extends toward the smaller electrode due to the presence of trapped holes on the larger electrode side. This approach facilitates efficient charge carrier separation and collection, leading to self-powered operation across a wavelength range of 300–1000 nm at 0 V bias. The PD exhibits a high responsivity of 513 mA/W and detectivity of 2.04 × 1011 Jones at a wavelength of 1000 nm. Furthermore, the normalized photocurrent-to-dark current ratio (NPDR) analysis reveals the PD's superior dark current suppression capabilities, resulting in high sensitivity and reliable detection.