Effect of substrate temperature on F and Al co-doped ZnO films deposited by radio frequency magnetron sputtering

Abstract

In this study, F and Al co-doped ZnO (FAZO) films were fabricated by radio frequency (RF) magnetron sputtering technique using an AlF3-doped ZnO ceramic target. The effect of substrate temperature (Ts) on the structural, morphological, elemental, chemical states, electrical and optical properties of the FAZO films were systematically studied by X-ray diffraction, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectrometry, and ultraviolet–visible–near infrared spectrophotometry. The results show that the doping F and Al did not change the structure of the ZnO, and all films show a typical wurtzite structure with c-axis preferred orientation. As the Ts value increases, the surface morphology of the film changed from “pyramid” shape to “crater” shape and to smooth and dense. The doping effect of F and Al gradually appeared with the increase in Ts. The FAZO film exhibited good performance with mobility of 29.92 cm2/Vs, carrier concentration of 2.84 × 1020 cm−3, resistivity of 7.35 × 10−4 Ω cm, and average transmittance of nearly 90% in the optical spectral range of 400–1400 nm at Ts = 440 °C. When the FAZO films were used as front electrode material for perovskite thin film solar cells, a higher conversion efficiency was obtained compared with that of the AZO film used as reference.