Effect of high-energy electron beam irradiation on the properties of AZO thin films prepared by rf magnetron sputtering

We investigated that high-energy electron beam irradiation (HEEBI) performed in air at room temperature affected remarkably the properties of Al-doped ZnO (AZO) films grown on SiO2 substrates by radio frequency magnetron sputtering techniques. Hall and photoluminescence measurements revealed that the n-type conductivity was preserved in HEEBI treated films with low dose up to 1015 electrons/cm2 and converted to p-type conductivity with further increase in the amount of dose. X-ray photoelectron spectroscopy confirmed the conversion of conductivity by showing that in-diffusion of O2 from the ambient as well as out-diffusion of Zn from the films took place as a result of HEEBI treatment at high dose of 1016 electrons/cm2. X-ray diffraction analysis indicated that all as-grown films were found to have compressive stress, which was enhanced by HEEBI treatment with the increase of doses. It was also found that worse crystallinity with a smaller grain size was observed in HEEBI treated films with a higher dose, which was correlated with rougher surface morphologies of films observed by an atomic force microscope.