Ab initio study of electronic and optical properties of penta-SiC2 and -SiGeC4 monolayers for solar energy conversion

Strain- and electric field-enhanced optical properties of the penta-siligraphene monolayer

“…The numbers n and m denote removed/added C/Si atoms from/to the PG monolayer (PG used as a reference system). 46 The so obtained formation energy of the p-Si 2 C 4 monolayer is found to be À1.48 eV, and this result is close to that found using the modified Becke-Johnson (mBJ) method, 9 indicating the structural stability of the p-Si 2 C 4 monolayer. Moreover, in order to check the dynamic stability of the monolayer, the lattice dynamics phonon through the high-symmetry path in the Brillouin zone is studied via computing the phonon-dispersion curve as depicted in Fig.…”

“…Materials with medium electronic bandgaps (1-3 eV) are involved in various applications such as photocatalytic, optoelectronic and photovoltaic materials. 9,47,48 The electronic band structure of the p-Si 2 C 4 monolayer is computed using the PBE functional with the Fermi energy set to zero electronvolts. The calculated electronic band structure of the p-Si 2 C 4 monolayer is illustrated in Fig.…”

“…Li et al 8 found that this monolayer is thermodynamically stable with high carrier mobilities (up to 2500 cm 2 V −1 s −1 ) and small anisotropic effective masses. In addition, Bouziani et al 9 showed that the PSG monolayer has a large absorption and a small reflectivity in the visible range.…”

Enhancement in photocatalytic water splitting using van der Waals heterostructure materials based on penta-layers

“…18,19 In addition, some experimental and theoretical studies have revealed type-II bands in many heterostructures. [20][21][22][23][24][25][26][27] More recently, new 2D materials, namely, pentagonal monolayers such as p-Si 2 C 4 , p-Si 2 N 4 , p-SiGeC 4 , p-Ge 2 C 4 and p-ZnO 2 have been theoretically reported [28][29][30][31][32] using first-principles methods by proving their dynamic, thermal and mechanical stabilities. [32][33][34][35][36][37] Unfortunately, experimental investigations of the mentioned pentagonal materials have so far been unsuccessful, although other materials with similar structures have been identified experimentally.…”

“…In addition, the interesting feature of a semiconductor state with an indirect band gap, which can be tuned by doping, strain, external electric field and adsorption, 37,[41][42][43] makes the penta-layers suitable for various applications, including optoelectronics, thermo-electronics, photovoltaic technology, nanodevices and transparent electrodes. 29,30,32,33,44,45 Recently, numerous researchers have investigated heterostructures based on a combination of individual pentagonal monolayers and reported fascinating properties for future applications. [46][47][48][49][50] For example, Wang et al 46 found that the KAgSe/SiC 2 heterojunction exhibits a type-III band alignment that can be modified by a transition from type-III to type-I/II band alignment under external electric field.…”