Tuning Electronic Properties of the SiC-GeC Bilayer by External Electric Field: A First-Principles Study

Abstract

First-principles calculations were used to investigate the electronic properties of the SiC/GeC nanosheet (the thickness was about 8 Å). With no electric field (E-field), the SiC/GeC nanosheet was shown to have a direct bandgap of 1.90 eV. In the band structure, the valence band of the SiC/GeC nanosheet was mainly made up of C-p, while the conduction band was mainly made up of C-p, Si-p, and Ge-p, respectively. Application of the E-field to the SiC/GeC nanosheet was found to facilitate modulation of the bandgap, regularly reducing it to zero, which was linked to the direction and strength of the E-field. The major bandgap modulation was attributed to the migration of C-p, Si-p, and Ge-p orbitals around the Fermi level. Our conclusions might give some theoretical guidance for the development and application of the SiC/GeC nanosheet.

Insight into the stacking and the species-ordering dependences of interlayer bonding in SiC/GeC polar heterostructures

“…Such band gap is broadened to 2.242/3.054 eV (at PBE/ HSE06 level) under a 2.64% compression (figures S4(f) and (h)). Thus, both the band gap and the positions of the CBM and VBM can be modulated under strains, consistent with othe DFT calculations [27,29,30,33,[36][37][38][39][40][43][44][45][46][47][48][49][50].…”

“…the SiC layer gains more electrons from the GeC layer, as shown in figure 8 and table 2), which is consistent with a net electron flowing from GeC to SiC in the interfacial region (see figure 8). Meanwhile, there is a remarkable potential drop (ΔV ) between the SiC and GeC layers for all patterns (7.10-7.59 eV) (similar pattern was found in [46] for the AA stacking with C-C ordering), which is a rather large comparable to other 2D hetero-bilayers [47,48,[81][82][83][84][85][86][87][88][89]. Such a large potential drop supports the existence of a built-in electrostatic field across the interfacial region (shown in figure 8) which may affect carrier dynamics and will certainly enhance electron-hole separation.…”

“…Thus, they are 2D polar materials. Many studies have been performed by assembling the SiC (GeC) monolayer with other different layered materials to perform band structure engineering via tuning applied electric field, strain, twist angles, number of layers, etc [38,[43][44][45][46][47][48][49][50][51].…”

Evaluating Phonon Characteristics by Varying the Layer and Interfacial Thickness in Novel Carbon-Based Strained-Layer Superlattices

“…Semiconductor quantum wells (QWs) and superlattices (SLs) have formed the basis of fabricating many modern electronic and optoelectronic devices, including the light-emitting diodes (LEDs), laser diodes (LDs), field-effect transistors (FETs), etc. [1][2][3][4][5][6][7][8][9][10]. Compared with II-VI and III-V compounds, the epitaxial growth of C-based zinc-blende (zb) IV-IV (XC with X = Si, Ge, Sn) binary materials, alloys and heterostructures (i.e., QWs, SLs, etc.)…”

“…of higher thermal conductivity, wider electronic energy bandgaps, and higher mechanical strength have recently stimulated interest among the technologists to design different types of device structures (e.g., meta-photonic heterostructures, holographic displays, lasers, etc.) and for the scientists to evaluate their basic traits [1][2][3][4][5][6][7][8][9][10]. The progress in device engineering has Solids 2023, 4 288 demanded careful selection of the C-based wide-bandgap E g (SiC = 2.42 eV; GeC = 1.52 eV) materials which maintain physical properties both at elevated temperatures and higher radiation levels [2][3][4][5][6][7][8][9].…”