Effect of thickness on optoelectrical properties of Nb-doped indium tin oxide thin films deposited by RF magnetron sputtering

Niobium-doped indium tin oxide (ITO:Nb) thin films are prepared on glass substrates with various film thicknesses by radio frequency (RF) magnetron sputtering from one piece of ceramic target material. The effects of thickness (60–360 nm) on the structural, electrical and optical properties of ITO: Nb films are investigated by means of X-ray diffraction (XRD), ultraviolet (UV)-visible spectroscopy, and electrical measurements. XRD patterns show the highly oriented (400) direction. The lowest resistivity of the films without any heat treatment is 3.1×10 −4 Ω·cm −1 , and the resistivity decreases with the increase of substrate temperature. The highest Hall mobility and carrier concentration are 17.6 N·S and 1.36×10 21 cm −3 , respectively. Band gap energy of the films depends on substrate temperature, which varies from 3.48 eV to 3.62 eV.