| Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2018) | |
| Thin Films | Tuesday Sessions |
| Session TF-TuM |
| Session: | Innovations in the Development of Multifunctional Thin Films |
| Presenter: | Bastian Stoehr, University of South Australia, Australia |
| Authors: | B. Stoehr, University of South Australia, Australia E. Charrault, University of South Australia, Australia D. Evans, University of South Australia, Australia F. Lacroix, ENSCBP - Bordeaux INP, France J. Parks, University of Bath, United Kingdom P.J. Murphy, University of South Australia, Australia C. Hall, University of South Australia, Australia |
| Correspondent: | Click to Email |
Electro-magnetic (EM) transparent decorative coatings with a metallic appearance are highly desirable for military, automotive and communication applications. More specifically, they are advantageous as decorative coatings for consumer electronics. Such coatings will enable device to device communication with minimal attenuation of the signal. This will allow devices to save energy and result in increased battery life.
Inherently, a metallic thin-film, e.g. aluminium, interferes with EM radiation rendering it unsuitable for these applications. Hence, to create multifunctionality, aluminium was alloyed with semiconductors in order to manipulate its EM transparency, whilst maintaining the decorative properties of the metal thin film. One challenge for these coatings is to maintain their desired properties during thermal events, either during manufacturing into a final device or as a result of environment conditions during use.
Metal-semiconductor thin films have the inherent advantage that the optical and electrical properties of the thin film can be manipulated in multiple ways.1 The properties of the thin films can be controlled not only by changing the alloy composition (type and amount of semiconductor), but also by varying the deposition parameters. We report the influence of deposition parameters and thin film composition on the EM transparency, as well as the optical properties of these coatings.
We also report on their response to thermal stress. The optical and electrical properties of these thin films have been studied for relevant process temperatures of up to 240 °C. Their properties were analyzed and compared post processing. It was revealed that after processing the thin films at relevant temperatures, the properties changed. Interestingly, the magnitude and direction of change was dependent on the type of semi-conductor used. Possible mechanisms include oxidation, phase changes, grain formation, grain size changes and changes along grain boundaries. This information will be used to select composition and process properties so that aluminium-semiconductor alloys can be used in a number of applications.
1. Kawaguchi, T., Tahara, K. & Saga, T. Radio wave transmitting decorative member. (2008).