Laser Melting of Nanoparticulate Transparent Conductive Oxide Thin Films

Layers of ZnO nanoparticles with thicknesses of about 40 nm were prepared on silicon substrates. The layers were irradiated by single pulses of a 248 nm excimer laser, which proofed suitable for consolidation and significant densification of the particle layers under ambient conditions. Experiments as well as simulations have confirmed that the application of a SiO2 particle layer between the substrate and the ZnO particle layer can be used to hamper heat transfer towards the substrate. Thus the ZnO layer can be thermally insulated from the substrate while heating the ZnO up to its extremely high melting point. Consequently, such a layer stack could enable the application of consolidated particle layers on temperature-sensitive carrier substrates such as polymer foils which are to be used in low-cost mass production of devices like displays or solar cells.