Thin sputter deposited gold films on In2O3:Sn, SnO2:In, TiO2 and glass: Optical, electrical and structural effects

Thin gold films are promising transparent conductors with many actual and potential uses in “green” technologies, transparent electronics, etc. These applications require different substrate materials, and hence it is important to understand the role of the substrate on Au thin film growth. Such effects have been studied in this work wherein Au films—ranging from island structures, via large scale coalescence into meandering metal networks, to thin homogenous layers—were deposited by DC magnetron sputtering onto glass substrates and In2O3:Sn (ITO), SnO2:In and TiO2 base layers backed by glass. Optical, electrical and structural properties were recorded for films deposited onto unheated substrates. We found distinct and characteristic differences in Au growth on the various backings. Thus ITO and SnO2:In base layers yielded gold films with island features remaining to larger thicknesses than for deposition directly onto glass, and the sheet resistance was lower for gold deposition onto SnO2:In and ITO only when the gold films were less than ~5nm in thickness. Our results highlight the complexity of substrates' influence on thin film formation. [Display omitted] •Very thin metal films can serve as excellent transparent electrical conductors.•We studied Au films sputter deposited onto several different base layers backed by glass.•The base layer is important for the film's growth, transmittance and reflectance.•Deposition onto glass can lead to thinner contiguous films than deposition onto ITO and SnO2:In.