Strain-dependent electronic and optical properties of boron-phosphide and germanium-carbide hetero-bilayer: A first-principles study

Abstract

Opto-electronic properties of boron phosphide–germanium carbide (BP/GeC), a new van der Walls hetero-bilayer (HBL) with all possible stacking patterns, are studied under the density functional theory originated first-principles. The dynamical and chemical stabilities of the hetero-bilayer are confirmed by phonon spectra and binding energy. Among the dynamically stable HBLs, HBL 1 has the lowest binding energy with the smallest interlayer spacing of about 3.442 Å. Both values and natures (indirect or direct) of the electronic band structure are highly responsive to the stacking patterns. We have found that HBL 1 is indirect, while HBL 2 and HBL 3 become a direct bandgap at the K high symmetry point. All HBLs show type-II band alignment. Both compressive and tensile biaxial strains on the electronic properties of HBLs have been considered. All the HBLs become a direct bandgap for the compressive strain at 4% and 6%. We have also presented the optical property calculations on the HBLs, namely, the complex dielectric function and absorption properties, showing unique optical properties with significant absorption (5 × 105 cm−1 in HBL 2) in the whole solar spectra compared with their comprising monolayers. Moreover, the strain-dependent optical absorption coefficients with varying photon wavelengths are calculated and the maximum value is attained to be about 6.5 × 105 cm−1 in HBL 2 at 4% compressive strain. Consequently, the optoelectronic properties we have explored in our proposed new hetero-bilayer systems can guide the experimental realization of the hetero-bilayers and effective use in the future photovoltaic applications.

Tunable Photocatalytic Properties of Planar GaN/GeC Hetero-Bilayer: Production of H₂ Fuel

“…For GeC monolayer, the lattice constant a is 3.268 Å with a bond length of 1.887 Å [20]. These data are in good correspondent with former studies [26,42,43]. The stacking is made in such a way that the 2 × 2 GeC (a = b = 6.536 Å) monolayer is the bottom layer, and the 2 × 2 planar GaN (a = b = 6.496 Å) is vertically placed on the layer in six different stacking patterns.…”

Twist angle and electric gating controllable electronic structure of the two-dimensional stacked BP homo-structure

“…In addition, Joseph et al 22 found that changing the rotation angle between layers of the MoS 2 /BP heterostructure, and thus altering the type of band arrangement, can be not only useful for light-emitting diodes but also important for photovoltaic and photocatalytic applications. Khan et al 23 calculated the electron and optical properties of a BP/GaC heterojunction under specific strains by applying different strains, which is of great importance in the field of photovoltaic applications. In contrast to non-metallic materials, Mogulkoc et al 24 utilized black phosphorus and the BP heterostructure.…”

Robust ferromagnetism in two-dimensional GeC/CrN heterobilayers

“…Moreover, the GeC based heterobilayers are also extensively studied to tune the electronic properties of the desired heterosystem, i.e. , GeC/GaN, 6 GeC/SiC, 7 GeC/BP, 8 GeC/ZnTe, 9 and GeC/MoS 2 . 10…”

“…[1][2][3][4] The group-IV compound GeC film can be synthesized by various experimental procedures, such as chemical vapor deposition 5 making it compatible with industrial-scale production. Moreover, the GeC based heterobilayers are also extensively studied to tune the electronic properties of the desired heterosystem, i.e., GeC/GaN, 6 GeC/ SiC, 7 GeC/BP, 8 GeC/ZnTe, 9 and GeC/MoS 2 . 10 Recently the intrinsic long range magnetic order in 2D van der Waals crystals has attracted great interest since the experimental synthesis of various 2D magnetic crystals such as chromium trihalides (CrI 3 ), 11 Cr 2 Ge 2 Te 6 12 and Fe 3 GeTe 2 .…”