Investigations on high visible to near infrared transparent and high mobility Mo doped In 2O 3 thin films prepared by spray pyrolysis technique

Abstract

High visible to near infrared (NIR) transparent Mo (0–1 at%) doped In 2O 3 (IMO) thin films with high carrier mobility were deposited on Corning-1737 glass substrates at 400 °C by spray pyrolysis experimental technique. The films were annealed in vacuum (∼1×10 −4 mbar) at 550 °C for 45 min. XRD analysis confirmed that indium oxide belongs to cubic bixbyite structure. The preferred growth orientation along (2 2 2) plane for low Mo doping level shifts to (4 0 0) for higher Mo doping levels. Crystallite sizes extracted from the XRD data corroborate the changes in full-width at half-maximum due to the variation in Mo doping. Scanning electron microscopy study illustrates the evolution in surface microstructures as a function of Mo doping. The negative sign of Hall coefficient confirmed n-type conductivity. Films with high mobility of ∼149 cm 2/(V s), carrier concentration of ∼1.0×10 20 cm −3, resistivity of ∼4.0×10 −4 Ω cm and high figure of merit of ∼1.02×10 −2 Ω −1 were observed for post-annealed films (0.5 at% Mo). The obtained high average transparency of ∼83% in the wavelength range 400–2500 nm confirms that transmittance is well extended into the NIR region.