Effect of carrier gas species and flow rates on the properties of ZnO thin films prepared by chemical vapor deposition using zinc acetate dihydrate

ZnO thin films were prepared on (1 1 1) silicon substrates by sublimation of zinc acetate dihydrate utilizing argon and oxygen as the carrier gas. ZnO films prepared using oxygen as the carrier gas exhibit a week near-band-edge (NBE) emission and strong orange-red deep level emission, while ZnO films prepared using argon as the carrier gas shows a strong NBE emission and weak deep level green emission. The NBE emission energy position can be controlled to vary from 3.241 to 3.137 eV utilizing a combination of argon and oxygen as the carrier gas. Secondary ion mass spectroscopy analysis indicates that the relative concentration of carbon to hydrogen in the ZnO film remains constant, suggesting the presence of hydrocarbons. The concentration of hydrocarbon can be reduced by using oxygen in the carrier gas.