Magnetron-sputtered Mg-Ga co-doped ZnO transparent conductive thin films: Microstructural and optoelectrical investigation

Abstract

The Mg–Ga co-doped ZnO (MGZO) transparent conducting thin films (TCTFs) were fabricated via magnetron-sputtering. The dependence of microstructural, morphological and optoelectrical characteristics on sputtering power was investigated. The findings demonstrate that all the TCTFs present a wurtzite hexagonal crystal structure and (002)-preferred orientation. The sputtering power has a significant impact on the properties of the TCTFs. The sample fabricated at 150 W possesses the highest optoelectrical performance and crystalline quality, with the maximum figure of merit, highest average visible transmittance, minimum resistivity, lowest dislocation density and lattice strain of 1.042×104 Ω−1·cm−1, 92.21%, 1.181×10−3 Ω·cm, 1.041×1011 cm−2 and 3.936×10−3, respectively. Moreover, the optical constants (OCs) of the MGZO TCTFs were extracted by the optical spectrum fitting method (OSFM). The dispersion behavior of refractive index (RI) was assessed. The oscillator parameters, optical bandgaps and nonlinear OCs were realized. This study provides a reference basis for the applications of MGZO TCTFs in photoelectronic devices.