Characteristics of Ga-Al Doped ZnO Thin Films with Plasma Treatment Prepared by Using Facing Target Sputtering Method

Ga-Al-doped ZnO (GAZO) thin films were prepared on glass substrates using facing targets sputtering at room temperature. GAZO thin films have been treated in O-2 plasma to modify surface roughness in order to enhance the efficiency of OLED anodes made from the films. After deposition of the thin films, the substrate was subjected to plasma surface treatment. The electrical, optical, and surface properties of the deposited thin films were investigated by hall-effect measurement, UV/Vis spectrometry, and atomic force microscopy (AFM), respectively. As a result of increasing the plasma treatment time from 0 to 45 sec, the surface roughness of films after plasma treatment was improved, but their electrical, optical, and structural properties were slightly changed. The lowest values of the surface roughness were 1.409 nm for the as-deposited GAZO thin films for an O-2 plasma treatment time of 40 sec. All GAZO thin films have an average transmittance of 90% in the visible range (400-800 nm).