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CI 24‐Si: a Semiconducting Silicon Phase with an All‐sp 3 Bonding Network
Author(s) -
Lu Yihua,
Zhu Xi,
Wang Min
Publication year - 2018
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201702481
Subject(s) - band gap , direct and indirect band gaps , silicon , semiconductor , materials science , raman spectroscopy , diamond , phonon , phase (matter) , hybrid functional , dielectric , electronic band structure , effective mass (spring–mass system) , optoelectronics , condensed matter physics , semimetal , molecular physics , density functional theory , optics , chemistry , physics , computational chemistry , organic chemistry , quantum mechanics , composite material
A silicon allotrope which consists of 24 atoms in a body centered cubic cell and displays an symmetry (termed as cI 24‐Si) with a mass density of 2.38 g/cm 3 , is theoretically investigated. This silicon phase has an all‐sp 3 network with hexagons. Phonon dispersion confirms its dynamical stability and elastic constant implies it is mechanically stable. The analysis of electronic band structure performing by HSE06 functional shows that cI 24‐Si is an indirect semiconductor with a small band gap of 0.83 eV. Additionally, its direct band gap is only 0.02 eV larger than the indirect band gap, indicating that cI 24‐Si possesses a quasi‐direct band gap. The calculations of imaginary part of dielectric function and optical absorption for cI 24‐Si show that it has better optical properties than diamond‐like Si−I phase as it can capture more sunlight from visible to ultraviolet range. To provide more characterizations for future experimental observations, X‐ray diffraction patterns and Raman spectra are also theoretically simulated. Due to its small band gap, cI 24‐Si may possess potential electronic, optical and photovoltaic applications.