Electrochemical deposition of zinc oxide on a thin nickel buffer layer on silicon substrates

Electrochemical deposition of ZnO from aqueous nitrate solutions on nickel and platinum electrodes was investigated using the voltammetry technique to determine the optimal regimes in both potentiostatic and galvanostatic modes for acquiring polycrystalline ZnO films. Scanning electron microscopy, X-ray diffractometry, and X-ray microanalysis of the formed ZnO films are presented, showing a polycrystalline structure of the ZnO films with a preferable orientation in the (0 0 0 2) direction and an exact stoichiometric composition. The deposited ZnO films demonstrate a strong visible yellow-greenish photoluminescence at room temperature with a maximum at 600 um that can be referred to crystal lattice oxygen defects. The maximum of the photoluminescence excitation spectrum at 370 nm corresponds to the band gap of ZnO (3.3-3.35 eV) confirming that band-to-band excitation mechanism takes place. (C) 2011 Elsevier Ltd. All rights reserved.