Graphene–Insulator–Semiconductor Ultraviolet Light-Responsive Nitride LEDs for Multi-Applications

Abstract

Light emitting diodes (LEDs) are ubiquitous in our daily life nowadays. Among them, ultraviolet LEDs are unique because of their wide range of potential applications, spanning from biomedicine, environmental protection to public health. However, fabricating highly efficient and cost-effective ultraviolet LEDs still remains as a great challenge. In this work, a graphene–insulator–semiconductor (GIS) ultraviolet LED based on the mechanism of quantum tunneling has been designed, fabricated, and demonstrated, which possesses state-of-the-art multi-purposes, including electroluminescence, outstanding detection performance, and economical fabrication processes. The GIS ultraviolet device consists of an AlGaN thin film, a SiO2 insulating layer, and a graphene transparent electrode. Under a forward bias, the electroluminescence can be induced by the recombination of hole tunneling from graphene into the valence band edge of n-AlGaN and electrons in the conduction band with a high emission efficiency exceeding 10%. In addition, our GIS ultraviolet LEDs show an excellent ultraviolet-detecting capability and dual-side light emission, which can be used in optical communications and for the development of multifunctional optoelectronic devices. Notably, unlike the conventional LEDs, which requires both p-type and n-type doping of a semiconductor, the developed approach shown here only needs one type of doping. This approach can be applied to many other semiconductors with the inherent difficulty of both type of doping.