| With the rapid development of science and technology,the demand for devices with the characteristics of small size,high integration density and high performance is on the increase.Since the successful preparation of two-dimensional(2D)graphene,the research of 2D materials has become a popular realm of scientific research.Due to the limitation of a certain dimension,2D materials have completely different physical and chemical properties from their bulk materials.Furthermore,the reduction of dimensions has caused many strange quantum effects,which make the new 2D materials expected to meet the high requirements of semiconductor microelectronic devices.Recently,2D phosphorene has been successfully prepared experimentally.It has the characteristics of appropriate band gap,high carrier mobility,good electrical conductivity,as well as high switching ratio.That makes it a strong competitor in the field of semiconductor microelectronics.With the in-depth study of phosphorene materials,there are still some inherent deficiencies,such as easy decomposition under light conditions,and easy oxidation in air and water,which will seriously affect its practical application in the field of semiconductor devices.Therefore,we have to find a way to solve the oxidative problem and make phosphorene play an important role in semiconductor devices.Based on density functional theory(DFT),the first-principles calculations are used to systematically study the phosphorene's properties.The adsorption of sulfur atom at different concentrations and the effects of strain on the electronic structure of phosphorene were considered.The main research contents and conclusions of this paper are as follows: the electronic structure of black phosphorene was calculated by using the hybrid functional(HSE06)and PBE methods.Among them,the band gap value of black phosphorene calculated by HSE06 was 1.5 eV,and the band gap value calculated by PBE was 0.81 eV.The value is very consistent with other theoretical research results.Comparing the results calculated by the two methods,we can find that although the PBE calculation underestimates the band gap value,its analysis of the electronic configuration is the same as the result calculated by HSE06.At the same time,the HSE06 method is more time-consuming than the PBE method,so the subsequent calculations will be estimated using the PBE method.Then,we use sulfur atoms to adsorb on the surface of phosphorene to overcome the instability of phosphorene.When the sulfur atom is adsorbed on the surface of the phosphorene,the intrinsic band gap is increased from 0.81 e V to 1.06 eV.Black phosphorene has four different adsorption sites due to C2 h symmetry: top(T),bridge(B),hollow(H),and valley(V),the results show that the only adsorption site(V position)of sulfur atoms is completely consistent with the adsorption of oxygen atoms.We also explored the effect of sulfur atoms on the electronic structure of black phosphorene at different adsorption concentrations.Therefore,sulfur atom adsorption provides the possibility of passivation of phosphine.In this paper,we studied the single-sided adsorption and double-sided adsorption of the V position under the three supercellular structures of 2 × 2,3 × 3,and 4 × 4.By calculating the adsorption energy of sulfur atoms at different concentrations,it was found that double-sided adsorption is more stable than single-sided adsorption.Because the higher the concentration of black phosphorene is,the more easily passivation occurs.Therefore,we focused on the possibility of passivation of the strained black phosphorene under high concentration(11%).Therefore,we studied the tensile and compressive strains with a maximum applied stress of 10%.The calculation results show that when the tensile strain is greater than 8%,the passivation of phosphorene begins to occur.This discovery provides a new option for passivating black phosphorene.In this paper,the first-principles method of DFT was used to systematically study the effects on surface stability and electronic structure of phosphorene after the adsorption of sulfur atoms,and found that the V was the best adsorption site.And the structure that adsorbs sulfur atoms on the two-sided valleys of 2×2 supercells is the most stable.Moreover,the appropriate strain is used to effectively passivate the phosphorene.This article provides a variety of solutions for phosphorene passivation,which can effectively avoid the phosphorene from oxidation,and offers a feasible solution for the practical application of phosphorene in microelectronic devices such as field effect tubes,sensors,and electromagnetic electrodes. |
PDF Full Text Request