Crystallinity, order, the thin-film silicon continuum, and the spectral dependence of the refractive index in thin silicon films grown through ultra-high-vacuum evaporation for a range of growth temperatures

• Published in: Journal of non-crystalline solids Vol. 559; p. 120657
• Main Authors: Moghaddam, Saeed, Tay, Li-Lin, Noël, Mario, Zwinkels, Joanne C., Baribeau, Jean-Marc, Lockwood, David J., O’Leary, Stephen K.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2021
• Subjects: Crystallinity; Growth temperature; Order; Thin-film silicon continuum; Ultra-high-vacuum evaporation; Order; Growth temperature; Thin-film silicon continuum; Crystallinity; Ultra-high-vacuum evaporation
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/j.jnoncrysol.2021.120657

•The material we are examining is a unique form of thin-film silicon deposited at extremely low pressures.•We have connected the microstructure underlying these thin-films with their corresponding optical properties.•We place our thin-film silicon results into the framework of the thin-film silicon continuum.•The results are detailed and comprehensive. Using ultra-high-vacuum evaporation, thin-films of silicon were grown. This paper starts with a placement of our thin-films into the overall thin-film silicon continuum. Then, our thin-film’s Raman spectra are examined. In particular, two short-range order Raman related measures, namely the breadth and position of the Raman spectrum’s transverse-optic-peak, and an intermediate-range order Raman related measure, namely the ratio of the integrated transverse-acoustic and transverse-optic-peak intensities, are plotted as functions of the growth temperature. We then correlate these changes found in the nature of the order found within our thin-films of silicon with the changes observed in the spectral dependence of the refractive index, focusing on the maximum of the refractive index over the spectral range under consideration in this analysis. We find that the maximum of the refractive index increases in response to increased ordering. Finally, the potential device implications of these results are explored.