Enhanced sensing properties of defect-controlled ZnO nanotetrapods arising from aluminum doping

We report the synthesis of Al-doped ZnO nanotetrapods and investigate the effects on their sensing properties. It is found that Al doping introduces more defects based on the results of Raman and photoluminescence experiments and further confirmed by the sensing experiments. The green emission is enhanced and the relative intensity ratio between the green emission and the ultraviolet emission increases for Al-doped ZnO nanotetrapods. The ethanol sensing properties of ZnO nanotetrapods are effectively improved by Al doping. These can be explained in terms of the enhanced modulation of conductance caused by the preferential adsorption of the ethoxy on the oxygen vacancies. Our results provide an approach to exploit the improvement of gas sensitivity of ZnO nanomaterials.