Optical properties of ZnO films grown by atmospheric-pressure chemical vapor deposition using Zn and H2O as source materials

Zinc oxide (ZnO) films grown by atmospheric-pressure chemical vapor deposition using Zn powder and water (H2O) as source materials were investigated by photoluminescence (PL), photoacoustic (PA), Raman scattering, infrared (IR) absorption and attenuated total reflection (ATR) measurements. PL results suggested that the concentration of oxygen vacancy (VO) can be controlled by adjusting the source feed ratio of H2O to Zn (VI/II). PA measurements revealed that an absorption edge shifted to lower energies with increasing VI/II. It was also found that the increase in VI/II contributed to the decrease in resistivity. Raman, IR absorption and ATR spectra showed that the films contained high concentrations of hydrogen atoms. There is a possibility that the increase in concentration of hydrogen related donors contributes to both the VI/II dependence of PA spectrum and that of resistivity.