Influence of TiO2 Buffer on Structure and Optical Properties of ZnO Film on Si(100) Substrate

ZnO films were prepared on p-Si (100) substrates by direct current (DC) sputtering with and without TiO 2 buffer. The crystal structures, surface morphologies and optical properties were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and photoluminescence (PL). XRD results indicated that the growth mode of ZnO film was changed from strong (002) preferential orientation to several crystal orientations by introducing TiO 2 buffer, and the residual strain was reduced. SEM manifested that ZnO film with TiO 2 buffer had the uniform grain size and flat surface. In addition, stronger ultraviolet emission was observed from ZnO film with TiO 2 than that without at room temperature. The low temperature photoluminescence was investigated to understand the different PL mechanism of ZnO films.