Nonlinear properties of IGZO thin films prepared by RF magnetron sputtering

Abstract

Transparent conducting indiuim galium zinc oxide (IGZO) films were successfully grown on glass substrates at room temperature by rf magnetron sputtering. Structural, optical, morphological and electrical properties of IGZO films deposited at different rf power were investigated. Composition of the film was analysed by EDAX measurement which shows that percentage of Zn increased with the rf power. Surface morphology of the IGZO film measured from AFM analysis showed that the roughness of the film was increased with increase in RF power. The average transmission in the visible range was greater than 80% and the transmission in the higher wavelength region decreased with increase in RF power. The carrier concentration in IGZO films could be controlled by controlling rf power due to the increase of Zn/(Ga+In+Zn) ratio. Nonlinear properties of IGZO thin films were measured using z-scan technique. Increase in free electron concentration of IGZO thin films lead to a decrease of the corresponding nonlinear optical absorption response.