Fabrication and characterization of ZnO/Zn2TiO4/ZnAl2O4 composite films by using magnetron sputtering with ceramic targets

Transparent conducting oxides (TCO), including ZnO/Zn2TiO4/ZnAl2O4 composite films, are of considerable importance in optoelectronic applications. We fabricated composite film assisted with DC magnetron sputtering using ceramic target material (ZnO, TiO2, and Al2O3 powders mixture). The influence of processing gases composition (0-50% O-2-Ar) on film characteristics, including structural, optical, and electronic properties, is assessed. All films contain hexagonal wurtzite ZnO structure and ZnAl2O4, Zn2TiO4 spinel phases, with (002), (100), and (101) as dominant orientation by increasing oxygen contents. The transmittance of deposited films is above 81% (except for 50% oxygen), and the bandgap lies between 3.73 and 3.28 eV (reduced by oxygen addition). The carrier concentration and mobility increase with oxygen addition up to 25%, and resistivity de-creases by increasing oxygen contents. This study shows that using ceramic targets, the compound film with variable composition, structural and optoelectronic properties can be obtained by altering the gases admixture.