Li doped ZnO thin film: effect of substrate temperature on structure, optical and electrical properties

RF magnetron sputtering technique was employed to deposit Li-doped ZnO thin films onto quartz substrate at different substrate temperatures ranging from room temperature (RT) to 500 \(^{\circ }\hbox {C}\). X-ray diffraction analysis revealed that the deposited films had a hexagonal-wurtzite crystal structure with preferred orientation along the c-axis. Increasing the substrate temperature improved the crystallinity and caused a significant increase in the crystallite size (182 nm) for the film deposited at 500 \(^{\circ }\hbox {C}\). The energy band gap of the films deposited at RT, 350, 400, 450 and 500 \(^{\circ }\hbox {C}\) were found to be 3.292, 3.282, 3.281, 3.28 and 3.269 eV, respectively. All films exhibited a broad UV-violet emission band centered on 407 nm and attributed to the radiative recombination processes near the band edge. A Hall mobility of \(\sim \)33.3 \(\hbox {cm}^{2}\)/V s, concentration (\(n\)) of \(\sim \)7.6 \(\times 10^{18}\,\hbox {cm}^{-3}\) and resistivity of \(\sim \)39.7 \(\Omega \)-cm were obtained for the film deposited at 500 \(^{\circ }\hbox {C}\). The results show that the substrate temperature plays a crucial role in the structural, morphological, optical and electrical properties.