Single-step Zno nanorod bunches formation on p-type Si-conductive substrates by electrophoretic deposition

Abstract

To date, EPD obtained ZnO one-dimensional nanostructures have been achieved by depositing ZnO nanoparticles through a sacrificial anodic alumina membrane or promoted by the presence of pre-deposited Au nanoclusters on the substrate. In the present work, we explored using boron (p-type)-doped crystalline Si (100) substrates with different conductivities. We found the conditions for the direct self-assembly of one-dimensional ZnO nanorod bunches, in a novel and easy way, at room temperature. A colloidal dispersion of ≈5 nm-sized ZnO nanoparticles in 2-propanol was used. The results showed differences in the morphology of ZnO nanostructures depending on the Si substrate conductivity used. XRD patterns indicated that ZnO nanorods were preferentially formed in (002) direction corresponding to c-axis orientation in the wurtzite structure. Photoluminescence measurements revealed the presence of quantum confined excitons and high emission intensity in the visible range. Photoluminescence spectra showed that emission was dominated by the ZnO nanoparticles that form the nanostructures and not by the morphology or size of the nanostructures themselves. The results presented in this work expand the EPD technique applications to form nanorod nanostructures in a single step.