Evidence of sp2-like Hybridization of Silicon Valence Orbitals in Thin and Thick Si Grown on α-Phase Si(111)â3 × â3R30°-Bi.
Materials (Basel)
; 15(5)2022 Feb 25.
Article
em En
| MEDLINE
| ID: mdl-35268964
ABSTRACT
One-monolayer (ML) (thin) and 5-ML (thick) Si films were grown on the α-phase Si(111)â3 × â3R30°-Bi at a low substrate temperature of 200 °C. Si films have been studied in situ by reflection electron energy loss spectroscopy (REELS) and Auger electron spectroscopy, as a function of the electron beam incidence angle α and low-energy electron diffraction (LEED), as well as ex situ by grazing incidence X-ray diffraction (GIXRD). Scanning tunneling microscopy (STM), and scanning tunneling spectroscopy (STS) were also reported. The REELS spectra, taken at the Si K absorption edge (~1.840 KeV), reveal the presence of two distinct loss structures attributed to transitions 1sâπ* and 1sâσ* according to their intensity dependence on α, attesting to the sp2-like hybridization of the silicon valence orbitals in both thin and thick Si films. The synthesis of a silicon allotrope on the α-phase of Si(111)â3 × â3R30°-Bi substrate was demonstrated by LEED patterns and GIXRD that discloses the presence of a Si stack of 3.099 (3) Å and a â3 × â3 unit cell of 6.474 Å, typically seen for multilayer silicene. STM and STS measurements corroborated the findings. These measurements provided a platform for the new â3 × â3R30° Si allotrope on a Si(111)â3 × â3 R30°-Bi template, paving the way for realizing topological insulator heterostructures from different two-dimensional materials, Bi and Si.
Auger spectroscopy; Si K-edge; grazing incidence X-ray diffraction; low-energy electron diffraction; reflection electron energy loss spectroscopy; reflection high-energy electron diffraction; scanning tunneling microscopy and spectroscopy; silicene-like; sp2-like hybridization; α-phase Si(111)â3 × â3R30°-Bi
Texto completo:
1
Bases de dados:
MEDLINE
Idioma:
En
Revista:
Materials (Basel)
Ano de publicação:
2022
Tipo de documento:
Article
País de afiliação:
Itália