Khan Uzair, Saeed M Usman, Elansary Hosam O, Moussa Ihab Mohamed, Bacha Aziz-Ur-Rahim, Saeed Y
Department of Physics, Abbottabad University of Science and Technology Abbottabad KPK Pakistan
Department of Plant Production, College of Food Agriculture Sciences, King Saud University Riyadh 11451 Saudi Arabia.
RSC Adv. 2024 Feb 6;14(7):4844-4852. doi: 10.1039/d3ra07452h. eCollection 2024 Jan 31.
The structural, electronic and optical properties of silicene and its derivatives are investigated in the present work by employing density functional theory (DFT). The Perdew-Burke-Ernzerhof generalized gradient approximation (PBE-GGA) is used as the exchange-correlation potential. Our results provide helpful insight for tailoring the band gap of silicene functionalization of chlorine and fluorine. First, relaxation of all the materials is performed to obtain the appropriate structural parameters. Cl-Si showed the highest lattice parameter 4.31 Å value, while it also possesses the highest buckling of 0.73 Å among all the derivatives of silicene. We also study the electronic charge density, charge difference density and electrostatic potential, to check the bonding characteristics and charge transfer between Si-halides. The electronic properties, band structures and density of states (DOS) of all the materials are calculated using the PBE-GGA as well as the modified Becke-Johnson (mBJ) on PBE-GGA. Pristine silicene is found to have a negligibly small band gap but with the adsorption of chlorine and fluorine atoms, its band gap can be opened. The band gap of Cl-Si and F-Si is calculated to be 1.7 eV and 0.6 eV, respectively, while Cl-F-Si has a band gap of 1.1 eV. Moreover, the optical properties of silicene and its derivatives are explored, which includes dielectric constants and , refractive indices , extinction coefficients , optical conductivity and absorption coefficients . The calculated binding energies and phonon band structures confirm the stability of Cl-Si, Cl-F-Si, and F-Si. We also calculated the photocatalytic properties which show silicine has a good response to reduction, and the other materials to oxidation. A comparison of our current work to recent work in which graphene was functionalized with halides, is also presented and we observe that silicene is a much better alternative for graphene in terms of semiconductors and photovoltaics applications.
在本工作中，我们采用密度泛函理论（DFT）研究了硅烯及其衍生物的结构、电子和光学性质。采用佩德韦-伯克-恩泽霍夫广义梯度近似（PBE-GGA）作为交换关联势。我们的结果为通过氯和氟对硅烯进行功能化来调整其带隙提供了有益的见解。首先，对所有材料进行弛豫以获得合适的结构参数。Cl-Si的晶格参数最高，为4.31 Å，同时在所有硅烯衍生物中其起伏也最高，为0.73 Å。我们还研究了电子电荷密度、电荷差密度和静电势，以检查Si-卤化物之间的键合特性和电荷转移。所有材料的电子性质、能带结构和态密度（DOS）均使用PBE-GGA以及基于PBE-GGA的修正贝克-约翰逊（mBJ）方法进行计算。发现原始硅烯的带隙极小，但随着氯和氟原子的吸附，其带隙可以打开。计算得出Cl-Si和F-Si的带隙分别为1.7 eV和0.6 eV，而Cl-F-Si的带隙为1.1 eV。此外，还探索了硅烯及其衍生物的光学性质，包括介电常数ε1和ε2、折射率n、消光系数κ、光导率σ和吸收系数α。计算得到的结合能和声子能带结构证实了Cl-Si、Cl-F-Si和F-Si的稳定性。我们还计算了光催化性质，结果表明硅烯对还原有良好的响应，而其他材料对氧化有良好的响应。本文还将我们目前的工作与近期用卤化物对石墨烯进行功能化的工作进行了比较，我们观察到在半导体和光伏应用方面，硅烯是比石墨烯更好的替代品。
