Gholami Rudi Somayeh, Soleimani-Amiri Samaneh
Department of Electrical Engineering, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran.
Department of Electrical and Computer Engineering, Babol Noshirvani University of Technology, Babol 484, Iran.
J Phys Condens Matter. 2021 Apr 23;33(18). doi: 10.1088/1361-648X/abf0c4.
In this study, the density functional theory (DFT) is used to investigate the effects of passivating line sulfur vacancies by non-metal species (C, N, O, F, OH and NH) in armchair MoSnanoribbon (AMoSNR) on its structural, electrical and optical properties. Calculated binding energies show that passivation of line vacancies by oxygen atoms leads to the most stable structures. Electronic calculations show that presence of single line vacancies decreases the bandgap of 0.68 eV in perfect AMoSNR to 0.62 eV in single line vacant AMoSNR (SV) and substituting the vacancies with carbon and oxygen (C-SV and O-SV) returns the bandgap to its initial value. It is also shown that passivation of SV with NHleads to a semiconductor with a small bandgap of 0.08 eV. However, substituting the vacancies of SV with N, F and OH results in metallic structures. In the case of double line vacant AMoSNR (DV), the bandgap reduces significantly (0.38 eV) with respect to its perfect counterpart. Similar to what happened in SV, passivating DV with C and O again increases the bandgap to the bandgap of the perfect structure. Furthermore, N-, F-, OH- and NH-DV show metallic behavior. In addition, we use total, projected and local density of states (TDOS, PDOS and LDOS) analysis to reveal the role of different atoms in different positions on the electronic properties of defective AMoSNRs. In order to investigate the effect of passivation on the optical properties of defective AMoSNRs we present the real and imaginary parts of dielectric function spectra. Our results suggest that passivation of line vacancies by different atoms can efficiently tune the absorption of AMoSNR and open a new path to obtain MoS-based optoelectronic devices.
在本研究中，采用密度泛函理论（DFT）研究了扶手椅型二硫化钼纳米带（AMoSNR）中非金属物种（C、N、O、F、OH和NH）对线性硫空位的钝化作用对其结构、电学和光学性质的影响。计算得到的结合能表明，氧原子对线性空位的钝化导致了最稳定的结构。电子计算表明，单一线性空位的存在使完美AMoSNR的带隙从0.68 eV降低到单一线性空位AMoSNR（SV）中的0.62 eV，用碳和氧取代空位（C-SV和O-SV）可使带隙恢复到初始值。研究还表明，用NH钝化SV会导致形成带隙为0.08 eV的半导体。然而，用N、F和OH取代SV中的空位会导致形成金属结构。对于双线空位AMoSNR（DV），其带隙相对于完美结构显著降低（0.38 eV）。与SV的情况类似，用C和O钝化DV会再次将带隙增加到完美结构的带隙。此外，N-DV、F-DV、OH-DV和NH-DV表现出金属行为。此外，我们使用态密度（TDOS）、投影态密度（PDOS）和局域态密度（LDOS）分析来揭示不同位置的不同原子对缺陷AMoSNRs电子性质的作用。为了研究钝化对缺陷AMoSNRs光学性质的影响，我们给出了介电函数谱的实部和虚部。我们的结果表明，不同原子对线性空位的钝化可以有效地调节AMoSNR的吸收，并为获得基于MoS的光电器件开辟了一条新途径。
