Mg content regulating built-in electric field for self-powered ZnO/ MgxZn1-xO Schottky UV photodetector

In recent years, self-powered Schottky ultraviolet (UV) photodetectors (PDs) have attracted great attention due to their low manufacturing cost and zero-bias response. However, the development of high-performance self -powered Schottky devices is limited by the weak light response due to the internal weak electric field. Here, we introduce a MgxZn1-xO capping layer on ZnO and fabricate a ZnO/MgxZn1-xO heterojunction Schottky UV PD by using the sol-gel method. The improved device exhibits excellent self-powered characteristics and stability, specifically, an increase of 909% in photocurrent, an improvement of more than one order of magnitude in responsivity, and an improved linear dynamic region (LDR: 33.7 dB). The introduction of the MgxZn1-xO capping layer is responsible for the improved device performance, resulting in enhanced built-in electric field and depletion region width due to the increase of the Schottky barrier, thereby facilitating the separation and transport of photogenerated carriers. This work provides an effective way to fabricate high-performance self -powered ZnO Schottky UV PDs.