Thin films of PtAl<inf>2</inf> and AuAl<inf>2</inf> by solid-state reactive synthesis

Publication Type:
Journal Article
Citation:
Thin Solid Films, 2015, 589 pp. 805 - 812
Issue Date:
2015-01-01
Full metadata record
Files in This Item:
Filename Description Size
7.pdfPublished Version1.51 MB
Adobe PDF
© 2015 Elsevier B.V. The intermetallic compounds AuAl < inf > 2 < /inf > and PtAl < inf > 2 < /inf > are colored purple and yellow respectively. In the past they have been prepared by bulk melting techniques or by co-deposition in a magnetron sputterer. Here, however, we investigate films of AuAl < inf > 2 < /inf > , PtAl < inf > 2 < /inf > and (Au,Pt)Al < inf > 2 < /inf > prepared by sequential physical vapor deposition of the elements, followed by in situ solid-state reaction. The microstructure, dielectric functions, optical properties and thermal stability of the resulting films are characterized and compared to those prepared by bulk melting or co-deposition. The (Au,Pt)Al < inf > 2 < /inf > films show a color gamut that stretches from purple to brassy yellow depending on composition and microstructure. High temperature synchrotron X-ray diffraction experiments show that the (Au,Pt)Al < inf > 2 < /inf > phase is metastable, decomposing when heated above 420 °C. In contrast, the pure AuAl < inf > 2 < /inf > or PtAl < inf > 2 < /inf > phases are stable to about 580 °C before they oxidize or decompose. The alternative possibility of producing the purple-to-yellow color gamut by depositing optical stacks of very thin films of AuAl < inf > 2 < /inf > and PtAl < inf > 2 < /inf > is also assessed. Either scheme will provide a range of colors lying between those of the binary compound endpoints. Calculations predict that deposition of AuAl < inf > 2 < /inf > onto PtAl < inf > 2 < /inf > will produce more intense colors than vice versa, an unexpected finding that is worth further investigation.
Please use this identifier to cite or link to this item: