Photoluminescence and electroluminescence of ZnO:Zn layers prepared by a chemical vapor deposition method with ethanol addition

ZnO:Zn phosphor layers were prepared from ZnCl2 at relatively lower temperatures between 500 and 600 °C by a chemical vapor deposition method. Ethanol vapor was added in the deposition process. It produced the partially reducing conditions to form Zn-rich ZnO. The green photoluminescence (PL) around 500 nm was much enhanced by the ethanol addition. The highest PL intensity was obtained when the deposition temperature was 550 °C and 0.03 mol% ethanol was added to the gas. The effect of the ethanol addition was suppressed at temperatures higher than 600 °C, which was probably due to the complete decomposition of ethanol into H2O and CO2. The ZnO:Zn layers showed electric conductivity, and orange electroluminescence (EL) was emitted from the uncovered layers directly connected to the lead wires when ac-voltage was applied. The chromaticity coordinates of the EL was (0.52, 0.40).