Highly conductive Ga-doped ZnO thin films deposited onto Si wafers: Interface characterization

Undoped ZnO and Ga:ZnO films deposited onto Si wafer substrates have been prepared and characterized in order to investigate the suitability of Ga:ZnO as a transparent and conductive material. A comparative study between ZnO and Ga:ZnO properties using a wide variety of experimental techniques has been carried out. Our results prove the improvement of electrical and optical properties of Ga:ZnO films with respect to an undoped ZnO one. The interface between the film and the Si substrate has been explored in order to detect specific problems that could hinder an optimum electric contact between them. A very thin and abrupt Si/ZnO interface is observed using different characterization techniques, independently of doping. In spite of a dopant enrichment at the interface, the ZnO electronic band structure seems to smoothly adapt to the Si one.