Department of Physics, Faculty of Sciences, Ankara University, 06100, Tandogan, Ankara, Turkey.
Phys Chem Chem Phys. 2018 Nov 14;20(44):28124-28134. doi: 10.1039/c8cp05529g.
Motivated by the increasing number of studies on optoelectronic applications of van der Waals (vdW) heterostructures, we have investigated the electronic and optical properties of monolayer gallium nitride (MGaN) and boron phosphide (MBP) heterobilayers by using first-principle calculations based on density functional theory. We have ensured the dynamical stability of the structures by considering their binding energies and phonon spectra. We show that the magnitude and status (direct or indirect) of the band gap are strongly dependent on the stacking pattern of the heterobilayers. Furthermore, we have investigated the band splittings in the presence of an external electric field which show the effect of the field on the band alignment of the structure. We have also shown the band gap, charge redistributions and work function of the structures are highly dependent on the magnitude and direction of the electric field such that its magnitude yields indirect to direct band gap transitions around |E⊥| ∼ 0.7 V Å-1 at the Γ point and the order of the band gap is varied according to the direction of the electric field. Moreover, we examine optical properties of MGaN/MBP heterobilayers as part of DFT calculations. The band gap and work function being tunable with changes in the external field together with the prominent absorption over the UV range make the MGaN/MBP heterobilayer a feasible candidate for optoelectronic applications.
受到范德华（vdW）异质结构在光电应用方面研究数量不断增加的启发，我们使用基于密度泛函理论的第一性原理计算研究了单层氮化镓（MGaN）和磷化硼（MBP）异质双层的电子和光学性质。我们通过考虑它们的结合能和声谱来确保结构的动力学稳定性。我们表明，带隙的大小和状态（直接或间接）强烈依赖于异质双层的堆叠模式。此外，我们研究了在外电场存在下的能带分裂，这些分裂表明了电场对结构能带排列的影响。我们还表明，带隙、电荷重新分布和结构的功函数高度依赖于电场的大小和方向，以至于其大小导致在 Γ 点处 |E⊥| ∼ 0.7 V Å-1 左右的间接到直接带隙跃迁，并且带隙的顺序根据电场的方向而变化。此外，我们还作为 DFT 计算的一部分研究了 MGaN/MBP 异质双层的光学性质。带隙和功函数随着外场的变化而可调，加上在紫外范围内的显著吸收，使得 MGaN/MBP 异质双层成为光电应用的可行候选材料。
