Optical and electrical properties of tin-doped cadmium oxide films prepared by electron beam technique

Tin-doped cadmium oxide films were deposited by electron beam evaporation technique. The structural, optical and electrical properties of the films were characterized. The X-ray diffraction (XRD) study reveals that the films are polycrystalline in nature. As composition and structure change due to the dopant ratio and annealing temperature, the carrier concentration was varied around 1020 cm-3, and the mobility increased from less than 10 to 45cm2 V-1 s-1. A transmittance value of ~83% and a resistivity value of 4.4 × 10-4 Ω cm were achieved for (CdO)0:88(SnO2)0:12 film annealed at 350 oC for 15 min., whereas the maximum value of transmittance ~93% and a resistivity value of 2.4 × 10-3 Ω cm were obtained at 350 oC for 30 min. The films exhibited direct band-to-band transitions, which corresponded to optical band gaps of 3.1–3.3 eV