High near-infrared transparency and carrier mobility of Mo doped In2O3 thin films for optoelectronics applications

Abstract

Molybdenum (0–1 at. %) doped indium oxide thin films with high near-infrared (NIR) transparency and high carrier mobility were deposited on Corning-1737 glass substrates at 400 °C by a spray pyrolysis experimental technique. X-ray diffraction (XRD) analysis confirmed the cubic bixbyite structure of indium oxide. The preferred growth orientation along the (222) plane for the low Mo doping level (≤0.5 at. %) shifts to (400) for higher Mo doping levels (>0.6 at. %). The crystallite size extracted from the XRD data corroborates the changes in full width at half maximum due to the variation in Mo doping. A scanning electron microscopy study illustrated the evolution in the surface microstructure as a function of Mo doping. The negative sign of the Hall coefficient confirmed the n-type conductivity. A high carrier mobility of ∼122.4 cm2/V s, a carrier concentration of ∼9.5×1019 cm−3, a resistivity of ∼5.3×10−4 Ω cm, and a high figure of merit of ∼4.2×10−2 Ω−1 are observed for the films deposited with 0.5 at. % Mo. The obtained high average transparency of ∼83% in the wavelengths ranging from 400 to 2500 nm confirmed the extension of transmittance well into the NIR region.