Reinforcement role of GaP nanowires in a ZnO layer prepared by RF sputtering

This paper presents a thin nanocrystalline ZnO layer with embedded GaP nanowires (NWs). The NWs were grown in vapour-liquid-solid (VLS) mode by metal organic vapour phase epitaxy (MOVPE) at Au seeds formed from a very thin Au layer. The NWs were finally embedded in ZnO using deposition by RF sputtering combined with etching steps that resulted in a compact antireflection layer. We studied properties of such compact NWs structure by means of x-ray diffraction and atomic force microscopy. The study of mechanical properties was performed by nanoindentation measurements. The nanoindentation measurement showed that the incorporation of GaP nanowires into a ZnO layer led to increased hardness compared with that of a pure ZnO layer. The compact GaP NW/ZnO layer structure also exhibited some degree of pseudoelasticity. In addition, the mechanical properties of the compact nanowire layer are sufficiently robust to allow the thermo-compression bonding on the top of the structure.