Optical and electrical characterizations of vertically integrated ZnO nanowires

We report on the integration and characterizations of vertically aligned ZnO nanowires (NWs). Technological processes have been developed both for mineral and organic planarizations with suitable morphologies. Optical and electrical characterizations of these integrated NWs have been performed. A comparison of the photoluminescence (PL) spectra at 300 K of the as-grown and integrated NWs has shown no significant impact of the integration process on the crystal quality of the NWs. Photoconducting properties in the UV–visible range have been investigated through collective electrical contacts. A small increase of resistivity in ZnO NWs under sub-bandgap illumination has been observed and discussed. The electrical transport properties of vertically integrated single NWs have also been investigated by scanning spread resistance microscopy (SSRM). Surface depletion layers in ZnO NWs have been evidenced.