Semiconductor ultraviolet photodetectors based on ZnO and Mg_xZn_1−xO

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 Mg x Zn 1−x O, 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.

High-sensitivity β-Ga_2O_3 solar-blind photodetector on high-temperature pretreated c-plane sapphire substrate

“…Accordingly, solar-blind PDs can respond accurately to a very weak signal, even under sun or room illumination, and thus have an incomparable advantage over conventional UV PDs, especially for certain special applications, such as ozone-hole monitoring, fire detection, and missile threat warning [1,2]. Recently, solid-state PDs based on wide-bandgap semiconductors, including AlGaN [3], ZnMgO [4], diamond [5], and AlN [6], have been extensively explored for applications of solar-blind photodetection owing to their small size, light weight and low power consumption. However, the proportion of Al in AlGaN must exceed 40% to achieve a sufficiently large bandgap, which can generate high-density structural defects due to the slower atomic migration of Al than Ga and strong parasitic reactions [7].…”

Enhancement of photo-response via surface plasmon resonance induced by Ag nano-particles embedded in ZnO

“…ZnO is a promising material for opto-electronics in UV spectral ranges due to its direct band gap (3.37 eV), large exciton binding energy (60 meV), and high saturation velocity of electrons [1][2][3]. In recent years, lots of research efforts have been poured on the fabrication and optimization of high performance photodetectors based on ZnO in the form of either thin film [4,5] or nanostructures [6][7][8].…”

Mg-doped ZnO films prepared by chemical bath deposition

“…Zn 1-x Mg x O films with different Mg contents leading to cubic and hexagonal structures and largely different band gaps have been applied as gate insulator and channel in TFT devices [5]. Other applications include stimulated emission devices [6] and UV photodetectors [7]. Besides its remarkable properties, Zn 1-x Mg x O is a ''green'' material, as it consists of low-cost, earth-abundant and non-toxic elements.…”