Preparation and Characterization of R.F. Magnetron Sputtered Mo:ZnO Thin Films

The ZnO and Mo:ZnO thin films were deposited by radio frequency magnetron sputtering on quartz and intrinsic silicon (100) substrates at a fixed combined partial pressure 1×10−2 mbar of Ar + O2 and substrate temperatures of 473 K and 673 K. The effect of Molybdenum doping on ZnO thin films with different Molybdenum concentrations (1-2 atomic percent) was studied with the help of structural and microstructural characterization techniques. The films deposited at a substrate temperature of 473 K exhibited strong c-axis orientation with predominant (002) peak. At 673 K, along with (002) orientation, other orientations (100), (101), (220), and (103) were also observed. Among these, the (220) peak indicates the cubic phase of ZnO. With increasing Molybdenum concentration, the cubic phase of ZnO disappeared, and the (002) orientation became strong and intense. The composition analysis reveals that the undoped ZnO films deposited at 473 K have oxygen deficiency, and the ratio of Zn/O is improved with increasing Mo atomic percent in ZnO. The surface morphological features reveal that the undoped ZnO films were found to be uniform and have grain size of around 30 nm. The optical energy gap of the undoped ZnO films is 3.05 eV and increases with increasing Mo concentration. The thickness of the films is around 456 nm.