In the presented paper the structural properties of ZnO layers prepared by various methods are presented. Their surface morphology was investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Composition depth pro. ling was measured by secondary ion mass spectroscopy (SIMS). Layers deposited by RF diode sputtering from ZnO: Al2O3 target resulted in conductive ZnO:Al polycrystalline n-type layer. Nitrogen doped zinc oxide (ZnO: Al, N) layers were prepared by RF diode sputtering from the same target by different Ar/N-2 gas mixture ratio. The p-type conductivity of ZnO: Al, N layers have been caused by the incorporation of the nitrogen acceptor into ZnO. ZnO layers deposited by pulsed laser deposition (PLD) in O-2 atmosphere at substrate temperature of 400 degrees C showed both n-and p-type conductivity and polycrystalline grain formation. Additionally the structural and electrical properties of RF diode sputtered structures were investigated before and after annealing in temperature range of 400-600 degrees C. After annealing in N-2 atmosphere the conductivity of ZnO layer increased and ZnO/Si interface exhibited diffusion of Si into ZnO and O into Si. (C) 2008 Elsevier B. V. All rights reserved.