LED용 ZnO 투명산화물 전극의 특성향상

Abstract

Recently a number of researches have been carried out on transparent conducting oxide (TCO: ITO, ZnO) to replace metal electrode (Au/Ni) for enhancing the light extraction efficiency of LED. In this study, after co-doping Al and Ga to ZnO, the optical and electrical properties were investigated. The LED devices were fabricated using Al and Ga co-doped ZnO thin films for TCO. ZnO thin film was deposited on a (001) sapphire substrate by RF magnetron sputtering system at room temperature. The thickness of the ZnO thin film was kept to 270 nm. Resistivity and sheet resistance at room temperature were 4x10^(-4) Ωcm and 26 Ω/□, respectively. Transmittance at the visible wavelength range was more than 90%. voltage was5.8 V at 20 mA current. EL intensity of the LED device with ZnO TCO increased by 40% compared to that of Ni/Au. These electrical and optical properties suggest that ZnO is a potential candidate for transparent conducting oxide for LED applications.