Transformation of CaSi overgrowth domains to the CaSi₂ crystal phase via vacuum annealing

Abstract

The phase transformation of overgrown CaSi crystal on an (00l)-oriented epitaxial CaSi2 film was studied using high-angle annular dark-field scanning transmission electron microscopy. After annealing at 450°C under vacuum conditions, the CaSi domain transformed to the CaSi2 phase with thin Si layers. The transformed CaSi2 crystal formed epitaxially along the under-layer epitaxial CaSi2 film. The results suggest that Ca atoms in the overgrown CaSi domain diffused to the outermost passivated silicon oxide layer during the low-temperature vacuum anneal.

Electron-Beam Radiation Effects in Multilayer Structures Grown with the Periodical Deposition of Si and CaF2 on Si(111)

“…Ca 2 Si films are narrow-band semiconductor materials, and CaSi and CaSi 2 films are semimetals. On the basis of these silicides, approaches to obtaining materials with various functional properties are being developed [1][2][3][4][5][6][7][8][9][10][11][12][13]. Recently, we proposed a method for CaSi 2 synthesis using electron-beam irradiation during the growth of CaF 2 layers with molecular-beam epitaxy (MBE) [14,15].…”

Radiation-Stimulated Formation of Two-Dimensional Structures Based on Calcium Silicide

“…Recently, it was found that calcium-intercalated silicon atomic layers in CaSi 2 exhibit electronic properties typical of graphene-like materials [ 11 ]. Many scientific groups are currently involved in the research of calcium silicides [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. A variety of methods has been proposed to produce calcium silicides with different compositions that exhibit semimetallic or semiconducting properties.…”