LAUSR

Abstract In this work, we reported the effects of annealing temperature on the morphologies and electrical and optical properties of sputtered ZnO thin films grown on Si(100) and Si(111) substrates. Annealing at 600 °C leads to smooth and porous ZnO thin films (internal holes) with root mean square (RMS) surface roughness values of 0.56 and 0.81 nm on Si(100) and Si(111) substrates, respectively. In contrast, 900 °C annealing results in slightly rough, porous ZnO thin films with exposed holes and RMS surface roughness values of 6.1 and 6.5 nm for Si(100) and Si(111) substrates, respectively. XPS and photoluminescence spectra show that a high annealing temperature reduces the number of oxygen vacancies/defects and Zn defects and slightly decreases the binding energy for the Zn 2p3/2 peak. Meanwhile, metallic Zn was present in porous ZnO thin films grown on Si(111) substrates annealed at 600 °C but disappeared as the annealing temperature increased to 900 °C. In addition, the porous ZnO thin film grown on Si(111) substrate annealed at 900 °C exhibited the best optical properties and had only a few interstitial oxygen defects.