Stability, bonding, and electronic properties of silicon and germanium arsenides

Abstract

First‐principles calculations were carried out to study the stability, structural, and electronic properties of compounds of silicon arsenides (SiAs and SiAs2) and germanium arsenides (GeAs and GeAs2). The group IV atom (Si or Ge atom) is four‐coordinated and the As atom is three‐coordinated in both monoclinic and orthorhombic structures, which are energetically favored based on the calculated formation enthalpies for Si/Ge monoarsenides and diarsenides, respectively. The calculated SiAs bond lengths are slightly smaller than the GeAs bond lengths. In agreement with the experimental results, our calculations show both silicon arsenides and germanium arsenides are semiconductors. The calculated bandgaps of germanium arsenides are slightly smaller than those of silicon arsenides, which may be related to the lower ionicity of the GeAs bonds in germanium arsenides. The calculated density of states (DOS) of As atoms in the four compounds are somewhat different from each other indicating the difference of their local atomic environments. The calculations show that Si/Ge arsenides with Si/Ge vacancies are metals, which may be due to the unsaturated As atoms near the vacancy sites.

Anisotropic 2D SiAs for High‐Performance UV–Visible Photodetectors

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to their low-symmetry monoclinic or orthorhombic unit cells. [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] Their inplane anisotropic structures originate from unequal bond angles and strengths along the two in-plane crystallographic axes (i.e., the armchair and zigzag directions). In the past few years, much attention has been focused on the quantum-confinement effect on bandgap structures.

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“…The monolayers have wide bandgaps (2-3 eV) that are much larger compared to the bulk by at least 1 eV. [16][17][18][19][20][21][22][23][24][25] The widened bandgap allows efficient collection of visible light photons, and the bandgap positions are appropriate for visible-light-driven water splitting. The anisotropic absorption spectrum of GeAs, GeAs 2 , and SiAs 2 has been predicted by calculations.…”

Few‐Layer GeAs Field‐Effect Transistors and Infrared Photodetectors

“…These promising properties have intrigued continuous searching for novel 2DSCs. Recent theoretical studies [20,21] have revealed another large family of 2DSCs with tunable bandgap, which includes IV-V group compound germanium and silicon monopnictides (e.g.…”

“…GeAs and SiAs). Although early studies have inspected their lattice structure, [21] bandgap, [20] Hall mobility, [22] and thermoelectric performance [23] in bulk crystals, there are no reports of electrical properties based on few-layer flakes. Here, we report, for the first time, the semiconducting electronic properties of two-dimensional GeAs.…”

Computational exploration of two-dimensional silicon diarsenide and germanium arsenide for photovoltaic applications

“…However, they did not report the band structure or the band gap values of these materials. Later, Wu et al performed theoretical studies on silicon and germanium arsenides [ 9 ] to predict and reaffirm that m-SiAs/GeAs and o-SiAs 2 /GeAs 2 are indeed semiconductors. The studies were based on band-structure calculations and are in agreement with experimental observations.…”