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

Abstract

This paper deals with high transparent and high conductive oxides based on polycrystalline titanium (Ti) doped (0.5–3at.%) 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 ~97cm2V−1s−1, a carrier concentration of ~1.55×1020cm−3 and a resistivity of ~4.11×10−4Ω-cm with ~83% of transmittance in the wavelength ranging between 400 and 2500nm were obtained for 2at.% 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 2500nm 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.