Resistivity Stability of Ga Doped ZnO Thin Films with Heat Treatment in Air and Oxygen Atmospheres

T. Prasada Rao, M. C. Santhosh Kumar
2012 Journal of Crystallization Process and Technology  
The effect of annealing in air and oxygen on structural, electrical and optical properties of gallium doped ZnO thin films was investigated. The X-ray diffraction patterns showed that the films were highly preferentially oriented along (002) plane. After the heat treatment in air and oxygen environments, the intensity of (002) peak was apparently improved. It was found that heat treatment in air atmospheres lead to increase in surface roughness of the film. The GZO films annealed in oxygen at
more » ... aled in oxygen at 673 K exhibited low resistivity of 4.21 × 10 -3 Ω·cm, while the resistivity of film annealed in air showed a slightly higher value of 7.14 × 10 -3 Ω·cm. In addition to this, all films have good optical transmittance about 80% in the visible region. It is found from the photoluminescence studies that the broad visible emissions in GZO films originated from the intrinsic shallow traps (V Zn ) and deep level vacancies (Z ni , O Zn and V O ). Experimental Spray pyrolysis is an effective method for the deposition of GZO thin films. The precursor solution for spray pyrolysis was prepared by dissolving an appropriate amount of zinc acetate dehydrate and gallium nitrate in the mixture of deionized water and ethanol at room temperature. In this mixture, ethanol concentration was 10 ml in 100 ml solution. A few drops of acetic acid were added to aqueous solution to prevent the formation of hydroxides. The concentration of gallium was 3 at%. The total concentration of the solution was maintained at 0.2 mol·L -1 . The glass substrates were cleaned thoroughly with acetone,
doi:10.4236/jcpt.2012.22010 fatcat:dofbxtbkm5ex5oleet3fq3n3gm