The enhanced conductivity and stability of AZO thin films with a TiO2 buffer layer

Abstract Aluminum doped zinc oxide (AZO) films were substitutes of the SnO 2 :F films on soda lime glass substrate in the amorphous thin-film solar cells due to good properties and low cost. In order to improve properties of AZO films, the TiO 2 buffer layer had been introduced. AZO films with and without TiO 2 buffer layer were deposited on soda lime glass substrates by r.f. magnetron sputtering. Subsequently, one group samples were annealed in vacuum (0.1 Pa) at 500 °C for 120 s using the RTA system, and the influence of TiO 2 thickness on the properties of AZO films had been discussed. The XRD measurement results showed that all the films had a preferentially oriented (0 0 2) peak, and the intensity of (0 0 2) peak had been enhanced for the AZO films with TiO 2 buffer layer. The resistivity of TiO 2 (3.0 nm)/AZO double-layer film is 4.76×10 −4  Ω cm with the maximum figure merit of 1.92×10 −2  Ω −1 , and the resistivity has a remarkable 28.7% decrease comparing with that of the single AZO film. The carrier scattering mechanism of TiO 2 (3.0 nm)/AZO double-layer film had been described by Hall measurement in different temperatures. The average transmittance of all the films exceeded 92% in the visible spectrum. Another group samples were heat treated in the quartz tube in air atmosphere, and the effect of TiO 2 thickness on thermal stability of AZO films had been discussed.