Effect of film thickness on properties of Al-doped ZnO film as transparent conducting electrodes in OLEDs

Al-doped ZnO (AZO) thin film is a promising alternative to an ITO electrode in organic light-emitting diodes applications due to its low price, non-toxicity and other promising properties. In this paper, AZO thin films of different thicknesses were deposited on glass substrates as transparent conducting films by sputtering. The effect of film thickness on the structural, electrical and optical properties of AZO films were investigated. Results show that with the increase of film thickness, the electrical conductivity increase but the optical transmittance decrease. The optimum properties were obtained in 874 nm film, which exhibited an excellent figure of merit (27.8 × 10^-3Ω^-1) with transmittance of 84.4% and resistance of 5.72 × 10^-4Ωcm.