Influence of annealing temperature on some properties of TiO2/Au thin films prepared by rf and dc magnetron sputtering methods

Abstract

This paper uses RF and DC magnetron sputtering techniques to prepare TiO2/Au thin film on glass substrates. TiO2thin film was deposited under a power of 150 Watt for 90 min. by RF magnetron sputtering technique and achieved 132.6 nm thickness, while Au thin film was deposited under a power of 20 Watt for 15 min. by DC magnetron sputtering technique achieving 20 nm thickness. Afterward, these samples were annealed in different temperatures (150, 200, 250 and 300) ºC respectively for about 1 hr that led these thin films to be more crystalline in structure after annealing. X-ray Diffraction (XRD) revealed a high grain size equal to 9.077nm, which has a sharp peak R(220) at 64.65 º in 300 ºC. Atomic force microscopy (AFM) showed the structural properties as the average roughness after annealing about 4.68 nm in 300 ºC. All the obtained films are highly oriented in direction having nanocrystalline phase. The optical properties were examined by UV-VIS spectroscopy that showed increases in transmittance in the range of 35 % - 75 %, absorption coefficient from the region of high absorbing wavelength at 400nm, and reduction in energy gaps to (3.25 eV, 3.12 eV, 3.01 eV, and 2.95 eV) when annealing temperatures were increased. These results indicated the most suitable growth conditions for obtaining high-quality sputtered TiO2/Au thin films with a higher transparency performance for solar cells applications.