Strategies to control the spectral properties of Au–Ni thin films

• Published in: Thin solid films 2014-01, Vol.551, p.200-204
• Main Authors: McPherson, David J., Supansomboon, Supitcha, Zwan, Benjamin, Keast, Vicki J., Cortie, David L., Gentle, Angus, Dowd, Annette, Cortie, Michael B.
• Format: Article
• Language: English
• Subjects: Ab initio calculation; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Control equipment; Cross-disciplinary physics: materials science; rheology; Deposition by sputtering; Dielectrics; Exact sciences and technology; Gold; Gold–nickel; Materials science; Mathematical models; Methods of deposition of films and coatings; film growth and epitaxy; Methods of nanofabrication; Multilayers; Optical properties; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of specific thin films; Physical vapor deposition; Physics; Spectra; Strategy; Thin films
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2013.11.115

Gold and nickel have quite different dielectric functions. Here we use a combination of calculation and sample manufacture to assess two strategies by which thin films of these elements can be produced with a controlled range of far-field optical properties. In the first approach, control can be achieved by manipulating the density of states of metastable solid solutions, which in turn controls the dielectric function. In the second approach the optical properties of the films are controlled by varying the geometry of stacks fabricated from the constituent elements. We show that the two approaches can produce equivalent results so both are viable options in practice. Modeling is used to reveal how the structure controls the optical properties and to map out the possible color gamut. Predictions are tested with thin film samples fabricated by magnetron sputtering. •Optical properties of metastable (Au,Ni) calculated using density functional theory•Properties of nanoscale stacks of Au and Ni calculated using optical film theory•Alloying of Au and Ni allows for extensive control of optical properties.•An equivalent color gamut can be achieved by nanoscale stacks of the pure elements.•Predictions of color gamut verified using samples fabricated by magnetron sputtering