Structural, electrical, and optical properties of hydrogen and Cu codoped ZnO films prepared by magnetron sputtering at two substrate temperatures

Abstract

The Cu-doped ZnO films were prepared by varying H2 flux at substrate temperature (Ts) of 150 and 300 °C, and their structure and electrical-optical properties were investigated by XRD, SEM, AFM, XPS, Raman spectra, resistivity, transmittance spectra and PL spectra. The results indicate that the films prepared at 300 °C have thinner thickness, lower crystallinity, and larger surface roughness than those at 150 °C after introducing H2. By comparison, Zni and Cu contents are higher but VO content is lower in the films at 300 °C. It is found that Raman scattering peaks are mainly related to the type and number of point defects. Compared with films prepared at 150 °C, the films prepared at 300 °C have smaller resistivity but higher electrically conductive stability. The UV emission of films is significantly enhanced at higher H2 fluxes at both Ts. Relatively speaking, the Eg is smaller and UV emission is weaker after introducing H2 at 300 °C. The violet-blue and green-yellow emissions in the films are mainly derived from Zni and VO, respectively. Various possible functions of hydrogen were discussed, and the changes of the structure and optical-electric properties of the films with H2 flux and Ts were explained accordingly.