High near-infrared transmittance, high intense orange luminescence in vanadium doped indium oxide (V: In2O3) thin films deposited by electron beam evaporation

The V (5 wt.%) doped In2O3 (V: In2O3) thin films with the thickness of 50-150 nm were deposited on to glass substrate by electron beam evaporation technique and the deposited films were annealed at 200 °C in air for 2 h. The annealed films were characterized by structural, electrical, optical and photoluminescence properties. X-ray diffraction (XRD) pattern shows that the film is an amorphous nature. The negative sign of the Hall coefficient indicates the n-type conductivity. Experimental results show that the resistivity and transmittance of the films are strongly influenced by film thickness and post deposition annealing. A minimum resistivity of 6.22 × 10−3 Ω cm, a carrier concentration of 5.23 × 1019 cm−3, a Hall mobility of 19.21 cm2 V−1 s−1 and a figure of merit of 1.04 × 10−4 Ω−1 are observed for the film with thickness of 150 nm. After annealing the films, the average transmittance is enhanced up to 84% in the near infrared region. The blue-shift of optical band gap is found to increase from 1.62 to 2.25 eV with increasing the thickness, whereas the refractive index decreases from 2.92 to 2.64. Structural disorder was observed from the Urbach's tail. A prominent and high intense orange emission is achieved at room temperature, which may be attributed to oxygen deficiencies or intrinsic defects.