Semiconductor ultraviolet photodetectors based on ZnO and Mg_<i>x</i>Zn_1−<i>x</i>O

Abstract

It is indispensable to develop wide-band-gap based ultraviolet (UV) photodetectors (PDs), which are one of the basic building blocks of solid state UV optoelectronic devices. In the last two decades, we have witnessed the renaissance of ZnO as a wide-band-gap semiconductor and an enormous development of ZnO-based UV PDs as a result of its superb optical and electronic properties. Since the first demonstration, a great variety of UV PDs based on ZnO and its related materials have been proposed and demonstrated. These PDs, with diverse device geometries, exhibit either high performance or multiple functions, reflecting a state-of-the-art technology of UV optoelectronics. In this review, we study the latest progress of UV PDs made on ZnO and MgxZn1−xO, which is a representative alloy of ZnO for band-gap engineering techniques. The discussion focuses on the device performance and the behind device physics according to the architecture of UV PDs.