Effect of a buffer layer on microstructural evolution in ZnO/Si heterostructures

We have deposited ZnO thin films on Si(lll) substrates with and without a low temperature-grown ZnO buffer layer by using radio-frequency (rf) magnetron sputtering. The microstructural properties of ZnO/Si heterostructures have been investigated by using X-ray diffraction (XRD), pole-figures and transmission electron microscopy (TEM) measurements. The results of XRD, pole figures and TEM showed that both ZnO thin films with and without an embedded buffer layer had highly c-axis preferred orientations. When low-temperature-grown ZnO was used as an embedded buffer layer, the crystal quality of the ZnO thin films was improved due to the reduced rotation of the c-axis, despite its smaller grain size.