Abstract
The crystal structures, mechanical stability, anisotropy, electronic band structures, and effective mass of Pbca-SiC and Pbcn-SiC under pressure are calculated utilizing first-principles calculations. Pbca-SiC and Pbcn-SiC with pressures in the range of 0–50 GPa have thermodynamic and mechanical stability. Visible anisotropies are discovered by analyzing the two- and three-dimensional representations of Young’s modulus, which also change with increasing pressure. The band structure results forecast two wide bandgap semiconductors. Pbca-SiC is an indirect gap semiconductor with a value of 3.724 eV. It is worth noting that Pbcn-SiC is a direct gap semiconductor with a value of 3.639 eV, and the bandgaps of Pbcn-SiC decrease with increasing pressure, which makes the emission wavelength of Pbcn-SiC change from the near ultraviolet light zone to visible light zone. Based on the controllable direct bandgap, Pbcn-SiC has better application potential in light-emitting devices. Moreover, the carrier effective mass under ambient conditions is also calculated, and the minimum value of the electron effective mass is obtained in Pbcn-SiC with a value of 0.262m0, while the minimum value of the hole effective mass is found in Pbca-SiC with a value of −0.285m0.
Highlights
Electronic band structure computations are executed utilizing the HSE06 (Heyd–Scuseria–Ernzerhof)[43,44] hybrid functional, and the phonon spectra calculations are found by adopting the density functional perturbation theory (DFPT) method.[45]
It is worth noting that Pbcn-silicon carbide (SiC) is a direct gap semiconductor, which demonstrates that Pbcn-SiC has an application potential in light-emitting devices
The phonon spectrum and elastic constant results demonstrate that Pbca-SiC and Pbcn-SiC have dynamic and mechanical stability over a pressure range of 0–50 GPa
Summary
It is common knowledge that silicon carbide (SiC) has prominent properties, for instance, a wide bandgap, a large elastic modulus, high hardness and thermal conductivity, outstanding chemical stability, high electron saturation velocity, and a low coefficient of thermal expansion.[1,2,3,4,5,6,7,8,9,10,11,12] Based on the superior characteristics, SiC has a wide range of applications including in the nuclear, aerospace, biomedical, and semiconductor device industries.[13,14,15] the polytypes of SiC have more than 250 allotropes under ambient conditions and can be separated into three groups, so-called rhombohedral (R), cubic (C), and hexagonal (H) structures.[16–21] As a typical representative third-generation semiconductor with a wide range of bandgaps, many researchers have sought many new C–Si alloys, and their improved properties have been studied extensively.Over the past few years, many researchers have studied SiC polytypes, such as the F4 ̄3m (3C-SiC), P63mc (2H-, 4H-, and 6HSiC), P3m1 (10H-SiC), and R3m (3R-, 15R-, and 21R-SiC) symmetry groups, and some SiC polytypes have begun to be commercialized.[22–28] Recently, many novel SiC structures have been investigated by researchers based on first-principles calculations. It is common knowledge that silicon carbide (SiC) has prominent properties, for instance, a wide bandgap, a large elastic modulus, high hardness and thermal conductivity, outstanding chemical stability, high electron saturation velocity, and a low coefficient of thermal expansion.[1,2,3,4,5,6,7,8,9,10,11,12] Based on the superior characteristics, SiC has a wide range of applications including in the nuclear, aerospace, biomedical, and semiconductor device industries.[13,14,15] the polytypes of SiC have more than 250 allotropes under ambient conditions and can be separated into three groups, so-called rhombohedral (R), cubic (C), and hexagonal (H) structures.[16–21] As a typical representative third-generation semiconductor with a wide range of bandgaps, many researchers have sought many new C–Si alloys, and their improved properties have been studied extensively.
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