자외선 발광 칼슘실리케이트 기반 MOS 구조 발광소자

Abstract

The representative light sources that emit ultraviolet are discharge lamps and UV-LED, but those are bulky or limited emission form like spot. Therefore, ultraviolet emitting device with thin thickness and wide size has various application. In this research, UV emitting device has been implemented. The silicon wafer was used as a substrate, and it is composed of a thin film of nanoscale thickness, so it has very thin thickness and can be developed in a wide area. This device forms a 150 nm thick CaSiO3:Pr3+ phosphor thin film at the top of the n-type silicon wafer, and the upper and lower surface are attached with ITO transparent electrodes and Aluminum electrodes, respectively. Thin films phosphor was formed with a solution containing Ca and Pr ions through the spin-coating process and synthesized by 4 hours of heat treatment at 1200 °C in the air. Finally, metal-Oxide-Semiconductor (MOS) structure device is completed which consisting of layers of ITO, Oxide phosphor and Silicon semiconductors. Through AC drive, UV spectrum with 325 nm from pr3+ ions f-d transition and visible spectrum with 625 nm from f-f transition were measured. The Vth(Threshold voltage) of the device was 20 Vrms and breakdown occurred at 35 Vrms and it showed exponential increase in intensity and curve shape increase current when voltage increases.