The influence of deposition temperature on growth mode, optical and mechanical properties of ZnO films prepared by the ALD method

Nanocrystalline ZnO thin films were deposited on glass substrates via the atomic layer deposition (ALD) method at different temperatures ranging from 50 to 200 °C. The influences of deposition temperature on the film growth mode, growth rate, optical and mechanical properties of the ZnO films were investigated. At a critical temperature of 100 °C, ZnO films exhibited a series of changes. X-ray diffraction (XRD), atomic force microscopy (AFM), UV–vis spectra, room temperature photoluminescence (PL) spectra and nano-indentation measurement were used to analyze these variations.

► Nanocrystalline ZnO thin films were deposited on glass substrates via atomic layer deposition (ALD) method. ► The influences of deposition temperature on the film growth mode and growth rate of the ZnO films were investigated. ► The XRD spectrum shows a critical temperature of the ZnO (002) preferred orientation is 100 °C. ► Nano-indentation reveals that the hardness of (002)-orientation ZnO films increases with the increase of grain size. ► Increasing deposition temperature will decrease the optical band gaps of ZnO thin films but increases refractive index.