Hiramony Nishat Tasnim, Tanisha Tanshia Tahreen, Tabassum Sumaiya Jahan, Subrina Samia
Department of Electrical and Electronic Engineering, Bangladesh University of Engineering and Technology Dhaka 1205 Bangladesh
Nanoscale Adv. 2023 May 24;5(16):4095-4106. doi: 10.1039/d2na00918h. eCollection 2023 Aug 8.
We present a novel plumbene/hexagonal boron nitride (hBN) heterobilayer with intriguing structural, electronic, and optical properties. Three different stacking patterns of the bilayer are proposed and studied under the framework of density functional theory using first-principles calculations. All the stacking configurations display direct band gaps ranging from 0.399 eV to 0.432 eV in the presence of spin orbit coupling (SOC), whereas pristine plumbene possesses an indirect band gap considering SOC. Based on binding energy calculations, the structures are found to be stable and, consequently, feasible for physical implementation. All three structures exhibit low effective mass, ∼0.20 for both electrons and holes, which suggests improved transport characteristics of the plumbene/hBN based electronic devices. The projected density of states reveals that the valence and conduction band peaks around Fermi energy are dominated by the contributions from the plumbene layer of the heterobilayer. Therefore, the hBN layer is a viable candidate as a substrate for plumbene since charge carriers will only travel through the plumbene layer. Biaxial strain is employed to explore the dependence of the electronic properties like bandgap and effective mass of the heterobilayer on applied strain. We find that applied biaxial compressive strain can induce switching from the semiconducting to metallic state of the material. In addition, we explore various optical characteristics of both pristine plumbene and plumbene/hBN. The optical properties of the heterobilayer signify its potential applications in solar cells as well as in UV photodetectors.
我们展示了一种具有引人入胜的结构、电子和光学特性的新型铅烯/六方氮化硼（hBN）异质双层。在密度泛函理论框架下，使用第一性原理计算提出并研究了该双层的三种不同堆叠模式。在存在自旋轨道耦合（SOC）的情况下，所有堆叠构型都显示出0.399 eV至0.432 eV的直接带隙，而考虑SOC时，原始铅烯具有间接带隙。基于结合能计算，发现这些结构是稳定的，因此在物理实现上是可行的。所有三种结构都表现出低有效质量，电子和空穴的有效质量均约为0.20，这表明基于铅烯/hBN的电子器件的传输特性得到了改善。投影态密度表明，费米能级附近的价带和导带峰值主要由异质双层中铅烯层的贡献主导。因此，hBN层是作为铅烯衬底的可行候选材料，因为电荷载流子只会穿过铅烯层。采用双轴应变来探索异质双层的电子性质如带隙和有效质量对施加应变的依赖性。我们发现，施加的双轴压缩应变可以诱导材料从半导体状态转变为金属状态。此外，我们还探索了原始铅烯和铅烯/hBN的各种光学特性。异质双层的光学性质表明其在太阳能电池以及紫外光探测器中的潜在应用。
