Effect of Annealing Temperature on Photoluminescence of ZnO/Graphene Nano-films Deposited by Sol-gel Method

ZnO/graphene nano-films were directly prepared on Cu substrate via low pressure chemical vapor deposition (LPCVD) combined with a sol-gel method. The effects of the annealing temperature on the structure, morphology, the chemical state, component, and optical property of these ZnO/graphene nano-films were investigated. The XRD patterns demonstrate that the ZnO/graphene nanostructures exhibit the hexagonal wurtzite structure and the crystalline quality increases with increasing the annealing temperatures from 500 °C to 700 °C. When the annealing temperature reaches 700 °C, SEM analysis shows that sample film exhibits dense and uniform grains and smooth surface and the average grain size of film deposited 3 layers is about 35.7 nm. The PL measurement confirms that ZnO/graphene nano-film with deposited 3 layers at the annealing temperatures of 700 °C has a better optical performance, due to the higher crystalline quality and lower defect concentration.