Structural, electrical and optical properties of In2O3:Mo films deposited by spray pyrolysis

In2O3:Mo (IMO) films were deposited on glass substrates by spray pyrolysis. Transparent and conducting IMO films prepared with Mo contents [Mo/(Mo+In) atomic ratio] up to 14.89 at% were identified as Mo-doped In2O3 (In2O3:Mo) with preferred orientation (2 2 2). The IMO lattice is the same as that of the In2O3 cubic structure, with Mo6+ substituting for In3+ associated interstitial O2− in the In2O3. There are no new compounds in the IMO. The minimum resistivity and the maximum carrier concentration of the IMO films deposited at Mo content of 1.25 at% were 7.30×10−4 Ω cm and 4.98×1020 cm−3, respectively. The optical transmission of the sample deposited at a Mo content of 1.25 at% was about 90% in the wavelength range from 400 to 800 nm. The photoluminescence (PL) spectra of the sample revealed a multi-line structure which was identified in terms of exciton and exciton complexes with neutral donors and deep centers. The relative intensity of PL spectra of the IMO films decreased with increasing Mo content in the samples. The optical band gap of the IMO films deposited at a Mo content of 1.25 at% was 3.79 eV. The optical band gap of the IMO films decreased with increasing Mo content of the samples.