In order to determine the structures of Si（111）-√7 √3-In surfaces and to understand their electronic properties, we construct six models of both hexagonal and rectangular types and perform first-principles calcula...In order to determine the structures of Si（111）-√7 √3-In surfaces and to understand their electronic properties, we construct six models of both hexagonal and rectangular types and perform first-principles calculations. Their scanning tunneling microscopic images and work functions are simulated and compared with experimental results. In this way, the hex-H3＇ and rect-T1 models are identified as the experimental configurations for the hexagonal and rectangular types, respectively. The structural evolution mechanism of the In/Si（lll） surface with indium coverage around 1.0 monolayer is discussed. The 4×1 and -√7× √3 phases are suggested to have two different types of evolution mechanisms, consistent with experimental results.展开更多
The atomic and electronic structures of T1 and In on Si（111） surfaces are investigated using the firstprinciples total energy calculations. Total energy optimizations show that the energetically favored structure is...The atomic and electronic structures of T1 and In on Si（111） surfaces are investigated using the firstprinciples total energy calculations. Total energy optimizations show that the energetically favored structure is 1/3 ML T1 adsorbed at the T4 sites on Si（111） surfaces. The adsorption energy difference of one T1 adatom between （√3 × √3） and （1 × 1） is less than that of each In adatom. The DOS indicates that TI 6p and Si 3p electrons play a very important role in the formation of the surface states. It is concluded that the bonding of TI adatoms on Si（111） surfaces is mainly polar covalent, which is weaker than that of In on Si（111）. So T1 atom is more easy to be migrated than In atom in the same external electric field and the structures of T1 on Si（111） is prone to switch between （√3 × √3） and （1 × 1）.展开更多
Si(111)electrode has been widely used in electrochemical and photoelectrochemical studies.The potential dependent measurements of the second harmonic generation(SHG)were performed to study Si(111)electrode interface.A...Si(111)electrode has been widely used in electrochemical and photoelectrochemical studies.The potential dependent measurements of the second harmonic generation(SHG)were performed to study Si(111)electrode interface.At different azimuthal angles of the Si(111)and under different polarization combinations,the curve of the intensity of SHG with extern potential has a different form of line or parabola.Quantitative analysis showed that these differences in the potential-dependence can be explained by the isotropic and anisotropic contribution of the Si(111)electrode.The change in the isotropic and anisotropic contribution of the Si(111)electrode may be attributed to the increase in the doping concentration of Si(111)electrodes.展开更多
A kinetic Monte Carlo simulation is performed in order to study the effect of Sb as a surfactant on the growth of Ge/Si(111).In our model the exchange mechanism between Ge and Sb atoms and the re-exchange mechanism in...A kinetic Monte Carlo simulation is performed in order to study the effect of Sb as a surfactant on the growth of Ge/Si(111).In our model the exchange mechanism between Ge and Sb atoms and the re-exchange mechanism in which the exchanged Ge adatom re-exchange with the lifted Sb atom to return to the surfactant layer,are considered. Our simulation shows the re-exchange process plays an important role on the growth mode transition in Ge/Sb/Si(111) system.The influences of the substrate temperature and the deposition rate on the growth of Ge/Sb/Si(111) system is discussed.展开更多
基金V. ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （No.20603032, No.20733004, No.21121003, No.91021004, No.20933006）, the National Key Basic Research Program （No.2011CB921400）, the Foundation of National Excellent Doctoral Dissertation of China （No.200736）, the Fundamental Research Funds for the Central Universities （No.WK2340000006 and No.WK2060140005）, and the Shanghai Supercompurer Center, the USTC-HP HPC Project, and the SCCAS.
文摘In order to determine the structures of Si（111）-√7 √3-In surfaces and to understand their electronic properties, we construct six models of both hexagonal and rectangular types and perform first-principles calculations. Their scanning tunneling microscopic images and work functions are simulated and compared with experimental results. In this way, the hex-H3＇ and rect-T1 models are identified as the experimental configurations for the hexagonal and rectangular types, respectively. The structural evolution mechanism of the In/Si（lll） surface with indium coverage around 1.0 monolayer is discussed. The 4×1 and -√7× √3 phases are suggested to have two different types of evolution mechanisms, consistent with experimental results.
基金Supported by National Natural Science Foundation of China under Grant No.60476047Program for Science & Technology Innovation Talents in Universities of Henan Province under Grant No.2008HASTIT030
文摘The atomic and electronic structures of T1 and In on Si（111） surfaces are investigated using the firstprinciples total energy calculations. Total energy optimizations show that the energetically favored structure is 1/3 ML T1 adsorbed at the T4 sites on Si（111） surfaces. The adsorption energy difference of one T1 adatom between （√3 × √3） and （1 × 1） is less than that of each In adatom. The DOS indicates that TI 6p and Si 3p electrons play a very important role in the formation of the surface states. It is concluded that the bonding of TI adatoms on Si（111） surfaces is mainly polar covalent, which is weaker than that of In on Si（111）. So T1 atom is more easy to be migrated than In atom in the same external electric field and the structures of T1 on Si（111） is prone to switch between （√3 × √3） and （1 × 1）.
基金supported by the National Natural Science Foundation of China(No.21673251,No.21773258,No.21873104,and No.91856121)the Chinese Academy of Sciences(No.JKYYQ20180014)。
文摘Si(111)electrode has been widely used in electrochemical and photoelectrochemical studies.The potential dependent measurements of the second harmonic generation(SHG)were performed to study Si(111)electrode interface.At different azimuthal angles of the Si(111)and under different polarization combinations,the curve of the intensity of SHG with extern potential has a different form of line or parabola.Quantitative analysis showed that these differences in the potential-dependence can be explained by the isotropic and anisotropic contribution of the Si(111)electrode.The change in the isotropic and anisotropic contribution of the Si(111)electrode may be attributed to the increase in the doping concentration of Si(111)electrodes.
基金Supported by the Zhejiang Provincial Natural Science Foundation under Grant No.Y6100384
文摘A kinetic Monte Carlo simulation is performed in order to study the effect of Sb as a surfactant on the growth of Ge/Si(111).In our model the exchange mechanism between Ge and Sb atoms and the re-exchange mechanism in which the exchanged Ge adatom re-exchange with the lifted Sb atom to return to the surfactant layer,are considered. Our simulation shows the re-exchange process plays an important role on the growth mode transition in Ge/Sb/Si(111) system.The influences of the substrate temperature and the deposition rate on the growth of Ge/Sb/Si(111) system is discussed.
