Nanocrystal growth of single-phase Si1−xGex alloys

• Published in: The Journal of physics and chemistry of solids Vol. 93; pp. 121 - 125
• Main Authors: Giang, Nguyen Truong, Cong, Le Thanh, Dung, Nguyen Duc, Quang, Tran Van, Ha, Ngo Ngoc
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2016
• Subjects: DFT-GGA calculation; Nanocrystals; SiGe alloy; Single phase; DFT-GGA calculation; SiGe alloy; Nanocrystals; Single phase
• ISSN: 0022-3697; 1879-2553
• DOI: 10.1016/j.jpcs.2016.02.015

We present the formation of single-phase Si1−xGex (x=0.2, 0.4, 0.6, and 0.8) alloy nanocrystals dispersed in a SiO2 matrix. The studied samples were prepared by co-sputtering with excess Si1−xGex in SiO2 of approximately 33at%. Upon heat treatment, crystallization of Si1−xGex alloys was examined by using X-ray diffraction and high-resolution transmission electron microscopy measurements. Single structure of face-centered cubic nanocrystals in a space group Fd-3m was concluded. The average nanocrystal size (from 2nm to 10nm) and the lattice constant a of the single-phase Si1−xGex nanocrystals were found to increase with the Ge composition parameter x. Density functional theory-generalized gradient approximation calculation showed the replacement of Ge into the Si sites and vice versa. •Single-phase FCC structure of Si1−xGex alloy nanocrystals formed.•The average size (2–10nm) and lattice constant increased with Ge composition.•DFT-GGA calculation demonstrated the replacement of Ge into the Si sites.