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Thin Film growth and characterization of Ti doped ZnO by RF/DC magnetron sputtering M. Baseer Haider1 , Mohammad F. Al-Kuhaili1, and S. M. A. Durrani1, Venkatesh Singaravelu2, and Iman Roqan2 1 Physics department, King Fahd University of Petroelum & Mineral, Dhahran, 31261, Saudi Arabia 2

King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering Division, Thuwal 23955-6900, Saudi Arabia. ABSTRACT Thin film Ti doped ZnO (Ti-ZnO) film were grown on sapphire (0001) substrate by RF and DC magnetron sputtering. Films were grown at a substrate temperature of 250 oC with different Ti/Zn concentration. Surface chemical study of the samples was performed by X-ray photoelectron spectroscopy to determine the stoichiometry and Ti/Zn ratio for all samples. Surface morphology of the samples were studied by atomic force microscopy. X-ray diffraction was carried out to determine the crystallinity of the film. No secondary phases of TixOy was observed. We observed a slight increase in the lattice constant with the increase in Ti concentration in ZnO. No ferromagnetic signal was observed for any of the samples. However, some samples showed super-paramagnetic phase. INTRODUCTION ZnO has attracted much attention due to its wide band gap (3.2eV) and high exciton binding energy 62meV. These properties make ZnO a sought after material for high frequency optoelectronic devices, transparent conducting oxide, and spintronics applications that can work in harsh environment. [1-3]. Sato et al and Dietl et. al. predicted that transition metal doped ZnO based dilute magnetic semiconductors can have Curie temperature higher than room temperature. [4,5] This started a flurry of experimental research in this direction and ZnO has been doped with many transition metal elements like Co, Mn, Fe, Cu.[6-7 and references therein] However, there is little experimental work on the Ti doped ZnO for dilute magnetic semiconductor. It has been predicted that if ZnO is doped with Ti then it can exhibit magnetic properties.[8-10] Here we report the growth and study of Ti doped ZnO (Ti:ZnO) by RF/DC magnetron sputtering on sapphire(0001) substrate at substrate temperature of 250 oC. We have studied the effect of Ti/Zn concentration on the surface morphology, crystal structure and magnetic properties of the sample. EXPERIMENT Ti-doped ZnO thin films were prepared by RF/DC Magnetron sputtering on sapphire (0001) substrates at 250 oC. ZnO target (99.9% pure) used RF power and Ti target (99.99% pure) was sputtering by DC power. RF power was fixed at 150Watts whereas different DC power was used to prepare films of different Ti concentration. Shown in table 1 below is the DC power used for different samples. Substrates were sonicated in acetone and isopropanol for five minutes in each solution. After introducing the substrate in the chamber, the chamber was pumped down to 1.2 x 10-5 mbar. Argon was used as sputtering gas and Ar flow rate during the deposition was set to 5sccm and the chamber pressure during the growth was ~ 1.4 x 10-