The transparent conductive oxide layers are of great interest in recent researches because of their tunable properties which avail them to be used in varieties of applications. The important and most widely used TCO materials such as ITO and AZO films were prepared with three different layer thicknesses using DC sputtering system. The structural, optical and electrical characteristics of both ITO and AZO samples were analyzed and compared to reveal thickness dependent tunable properties of TCO materials. The maximum transmittance of 99.5% was obtained for AZO films at 600-700 nm wavelength range. The resistivity of ITO films was 200 times lesser than that of AZO films. The internal and external quantum efficiencies of ITO devices increased with increasing layer thickness whereas this situation was just opposite in case of AZO devices. The optical and electrical properties of ITO samples were found easily adjustable by changing layer thickness as compared to AZO samples. This study explores the strong association between the layer thickness and the properties of TCO films. This would be useful to extend the applications boundary of TCO materials.