Structural and optical properties of Cu-Zno films deposited by thermal evaporation

摘要

Polycrystalline zinc oxide (P-ZnO) films are deposited on glass substrates for 2 min exposure time (ETs) by thermal evaporation. These P-ZnO films are further exposed in evaporated Cu species (ECuS) for different (0.5, 1, 1.5 and 2 min) ETs. XRD patterns shows the development of different planes related to ZnO phase and confirms the deposition of P-ZnO films. The shift in diffraction angle of ZnO (101) plane confirms the doping of Cu in ZnO lattice. The preferential growth orientation of P-ZnO and Cu doped ZnO films strongly depends on Cu contents and substrate surface temperature raised during deposition process. The values of crystallite size, micro-strains, dislocation density and texture coefficient of Cu doped ZnO film (deposited for 1.5 min ETs) are found to be 30.16 nm, 0.072, 10.99 × 10-4 nm-2 and 1.66 respectively. SEM microstructure of P-ZnO film is changed with increasing ETs in ECuS. EDX analysis confirms the presence of Zn, Cu and O in the deposited films. The values of Eg of P-ZnO and Cu doped ZnO films are found to be 3.42, 2.89, 3.74, 3.65 and 2.67 eV respectively.