CVD growth of zinc oxide thin films on graphene on insulator using a high-temperature platinum catalyzed water beam

Abstract

The characteristics of zinc oxide (ZnO) films with different thicknesses grown on graphene, i.e., single-layer graphene (SLG) and multilayer graphene (MLG), on insulators at 500 °C using a reaction between dimethylzinc and high-temperature water generated by a catalytic reaction on Pt nanoparticles were investigated. The growth rate of continuous ZnO layer on MLG was higher than that of SLG. XRD patterns for the ZnO films exhibited an intense diffraction peak associated with (0002) plane and small ones associated with (10–10) and (10–11) planes, suggesting the grown hexagonal wurtzite ZnO is not perfectly along c-axis direction due to the nature of the used graphene structures. The FWHM values of the 2θ for ZnO (0002) were < 0.20° and 0.16° for ZnO on SLG and MLG, respectively. The photoluminescence at room temperature exhibited strong emission peak at 3.28 eV with no significant level of green emission indicating negligible defect density in the grown ZnO films. The results suggest that accurate optical bandgap cannot be determined from the transmittance spectra for the ZnO films with thickness and roughness higher than 1 µm and 20 nm, respectively. The results also suggest that the thickness of ZnO films should be below 1 µm in order to obtain acceptable level of transmittance in visible up to near infrared region.