High mobility and visible–near infrared transparent titanium doped indium oxide thin films produced by spray pyrolysis

This paper deals with high transparent and high conductive oxides based on polycrystalline titanium (Ti) doped (0.5–3 at.%) indium oxide (IO) thin films produced on glass substrates at 400 °C by spray pyrolysis technique. X-ray diffraction analysis confirmed the cubic bixbyite structure of indium oxide. A high mobility of ∼ 97 cm2 V−1 s−1, a carrier concentration of ∼ 1.55 × 1020 cm−3 and a resistivity of ∼ 4.11 × 10−4 Ω-cm with ∼ 83% of transmittance in the wavelength ranging between 400 and 2500 nm were obtained for 2 at.% Ti doping films, rivalling so to the best known transparent conducting oxide based on indium tin oxide. Moreover, the transmittance in the broad wavelength ranging between 400 and 2500 nm is over 83%, leading so to an increasing carrier generation towards the near infrared region of the spectrum, as required for applications such as solar cells. We also notice that increasing the doping concentration widened the optical band gap and caused a small Burstein–Moss shift, due to mobility decrease, as expected. - Highlights: ► Ti-doped indium oxide thin films produced by spray pyrolysis. ► High Lewis acid strength of Ti4+ than Sn4+. ► High mobility and high visible–NIR transparency.