Influence of annealing on the structural,optical and electrical properties of indium oxide films deposited on c-sapphire substrate

Indium oxide（In2O3） films were prepared on Al2O3（0001） substrates at 700 °C by metal-organic chemical vapor deposition（MOCVD）.Then the samples were annealed at 800 °C,900 °C and 1 000 °C,respectively.The X-ray diffraction（XRD） analysis reveals that the samples were polycrystalline films before and after annealing treatment.Triangle or quadrangle grains can be observed,and the corner angle of the grains becomes smooth after annealing.The highest Hall mobility is obtained for the sample annealed at 900 °C with the value about 24.74 cm2·V-1·s-1.The average transmittance for the films in the visible range is over 90%.The optical band gaps of the samples are about 3.73 e V,3.71 e V,3.70 eV and 3.69 eV corresponding to the In2O3 films deposited at 700 °C and annealed at 800 °C,900 °C and 1 000 °C,respectively.