Fabrication and opto-electronic characterization of ultrathin gold films with a copper oxide seed

Ultrathin materials emerged as game changers for Optoelectronics industry for integrated circuits, transistors, solar cells, light emitting diodes, photoconductors, light crystal displays and many other applications. In particular, there is a high interest in ultrathin metals since they can be employed in photovoltaics, transparent electrodes, micro-electromechanical systems (MEMS) and multifunctional coatings. The keypoint for obtaining few-nanometer noble metal films stands in adding a proper seed layer before the deposition of the metal film to change the type of growth and promote an uniform thin film. For example, a 0.5nm CuO seed directly deposited on the substrate can strongly influence the percolation point of Au UTMFs: this means that it is possible to have electrical conduction at ultra small thicknesses. Furthermore, the nanometric size allows excellent optical properties since the seed can be considered transparent. The possibility to have good conductivity without strongly affecting the transparency at small dimensions has pushed the study of the electrical and optical properties of these films. The fact that their size makes them sensible to small fabrication changes (as film thickness) or external factors (e.g. temperature, light) can be exploited in different ways in the optoelectronic industry (as in sensing, photovoltaic, light modulation and many others). At ICFO - Institute of Photonics Science, we fabricated Au UTMFs with a copper oxide seed and we developed an experimental setup with the aim to verify and control the electrical properties of the film in normal conditions and under different stimuli.