Solution derived ZnO:Al films with low resistivity

Abstract ZnO:Al thin films were prepared via chemical solution deposition, using 2-butoxyethanol as an alternative for 2-methoxyethanol, which is more commonly used, but acutely toxic. The precursor solutions can be readily spin coated. The phase, morphology, electrical and optical properties of the deposited films are investigated, by XRD (X-ray diffraction), scanning electron microscopy, a two-point contact measurement and UV–vis spectrophotometry respectively. This way, the effect of this solvent is investigated. The films are deposited on borosilicate glass substrates and were found to be continuous and smooth. XRD measurements show a highly preferential c-axis orientation. The effects of the thermal treatment profile and Al dopant concentration are studied with respect to the obtained electrical properties. Optimally, the electrical resistivity was lowered to 6.5 × 10 − 3  Ω cm after annealing at 450 °C in a 95% He/5% H 2 atmosphere.