Effects of lattice mismatches in In2O3/substrate structures on the structural, morphological and electrical properties of In2O3 films

Indium oxide thin films were deposited by ultrasonic spray technique on ITO coated glass and single crystalline Si (400) substrates at 400 °C. Lattice mismatch effect on the crystalline structure, surface morphology and electrical properties of these samples is then studied.  X-ray diffraction (XRD) and Raman spectroscopy patterns suggest that the films deposited on ITO coated glass substrate are polycrystalline in nature having a cubic crystal structure with a preferred grain orientation along the (222) plane. However, films deposited on Si wafer substrate, exhibit randomly oriented growth. The crystallite size varies from 18 to 66.5 nm. AFM topographical images revealed that the In2O3/ITO films follow 2D or layer-by-layer-growth. But in the case of In2O3/Si films, 3D or island growth becomes dominant. The In2O3/ITO films is found to exhibit a higher value of conductivity (σ = 5 × 102 Ω−1 cm−1) than the In2O3/Si films, and the low value of the RMS roughness (9.83 nm).