Micromechanical characterization of laser consolidated nanoparticle ITO layers

Indium tin oxide (ITO) is one of the few materials that combine optical transparency in the visible light spectrum with high electrical conductivity. These properties provide functionality in many optoelectronic applications but their application to certain fields is limited by the need to achieve advanced mechanical properties, hence requiring micromechanical characterization methods. In this paper, ITO coatings of 94-325 nm thickness are produced from spin-coating of nanoparticle ink followed by consolidation by nanosecond UV laser irradiation in ambient air. These ITO layers are investigated by nanoindentation and scratch testing, which provide measurements of their hardness, Young's modulus and scratch resistance. This allows understanding the effect of the process parameters on the mechanical properties of the layers. It is concluded that a laser fluence of 59 mJ/cm2 provides an effective mechanical consolidation of ITO particles up to 150 nm thickness.