The Experts below are selected from a list of 45 Experts worldwide ranked by ideXlab platform
Yukichi Shigeta - One of the best experts on this subject based on the ideXlab platform.
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local electronic states on two dimensional Nanoscale Island of si and ge fabricated on si 111 7 7 substrate
International Journal of Nanoscience, 2009Co-Authors: Yukichi Shigeta, Ryota Negishi, Masahiko SuzukiAbstract:Nanoscale Islands on semiconductor are a strong candidate as building block in nanodevices. In the nanoIsland, some local deformation is induced by the surface tension, which has a great influence on the electronic property of the nanoIslands. To study the electronic structure of two-dimensional (2D) nanoIslands of Si and Ge on the Si(111) 7 × 7 surface, we formed nanoIslands of the same size and measured with angle resolved ultraviolet photoelectron spectroscopy (ARUPS), scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS). We found that the nanoIsland shows a characteristic fine structure due to some strain. We also calculated a relation between the strain and electronic state based on the density-functional theory. In the calculation, the dangling-bond state at the strained adatom on the nanoIsland (SR state) shifts to lower energy, which has liner dependence with the height of the adatoms. The ARUPS spectrum and the STS show characteristic peaks corresponding to the SR state, whose energy depends on the deformation of the adatom. The height of the adatom on the nanoIsland estimated from the energy difference is consistent with a result of the STM measurement. The strain of adatoms can be estimated from the electronic structure.
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interrelations between the local electronic states and the atomic structures in the si Nanoscale Island on si 111 7 7 surface
Journal of Applied Physics, 2003Co-Authors: Ryota Negishi, Yukichi ShigetaAbstract:We have investigated local electronic states and atomic structures of a self-assembled Si nano-Island on Si(111)-(7×7) dimer-adatom-stacking fault (DAS) substrate by using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy. The normalized differential conductivity (dI/dV)/(I/V) spectra show several peaks, whose energies depend on each individual dangling bond site on the Island, and these states are different from dangling bond states on the (7×7) DAS substrate. STM images at the edge of the Island also show some interesting variations as a function of the sample bias voltage. The variations are explained by modifications of dangling bond states on T4 site atoms and on buckled dimer atoms in the vicinity of the edge. From these results, we find a detailed behavior of a redistribution of the electron charge to stabilize the atomic structure of the nano-Island.
Ryota Negishi - One of the best experts on this subject based on the ideXlab platform.
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local electronic states on two dimensional Nanoscale Island of si and ge fabricated on si 111 7 7 substrate
International Journal of Nanoscience, 2009Co-Authors: Yukichi Shigeta, Ryota Negishi, Masahiko SuzukiAbstract:Nanoscale Islands on semiconductor are a strong candidate as building block in nanodevices. In the nanoIsland, some local deformation is induced by the surface tension, which has a great influence on the electronic property of the nanoIslands. To study the electronic structure of two-dimensional (2D) nanoIslands of Si and Ge on the Si(111) 7 × 7 surface, we formed nanoIslands of the same size and measured with angle resolved ultraviolet photoelectron spectroscopy (ARUPS), scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS). We found that the nanoIsland shows a characteristic fine structure due to some strain. We also calculated a relation between the strain and electronic state based on the density-functional theory. In the calculation, the dangling-bond state at the strained adatom on the nanoIsland (SR state) shifts to lower energy, which has liner dependence with the height of the adatoms. The ARUPS spectrum and the STS show characteristic peaks corresponding to the SR state, whose energy depends on the deformation of the adatom. The height of the adatom on the nanoIsland estimated from the energy difference is consistent with a result of the STM measurement. The strain of adatoms can be estimated from the electronic structure.
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interrelations between the local electronic states and the atomic structures in the si Nanoscale Island on si 111 7 7 surface
Journal of Applied Physics, 2003Co-Authors: Ryota Negishi, Yukichi ShigetaAbstract:We have investigated local electronic states and atomic structures of a self-assembled Si nano-Island on Si(111)-(7×7) dimer-adatom-stacking fault (DAS) substrate by using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy. The normalized differential conductivity (dI/dV)/(I/V) spectra show several peaks, whose energies depend on each individual dangling bond site on the Island, and these states are different from dangling bond states on the (7×7) DAS substrate. STM images at the edge of the Island also show some interesting variations as a function of the sample bias voltage. The variations are explained by modifications of dangling bond states on T4 site atoms and on buckled dimer atoms in the vicinity of the edge. From these results, we find a detailed behavior of a redistribution of the electron charge to stabilize the atomic structure of the nano-Island.
S R P Silva - One of the best experts on this subject based on the ideXlab platform.
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pulsed laser induced Nanoscale Island formation in thin metal on oxide films
Physical Review B, 2005Co-Authors: S J Henley, J D Carey, S R P SilvaAbstract:he mechanisms controlling the nanostructuring of thin metal-on-oxide films by nanosecond pulsed excimer lasers are investigated. When permitted by the interfacial energetics, the breakup of the metal film into Nanoscale Islands is observed. A range of metals (Au, Ag, Mo, Ni, Ti, and Zn) with differing physical and thermodynamic properties, and differing tendencies for oxide formation, are investigated. The nature of the interfacial metal-substrate interaction, the thermal conductivity of the substrate, and the initial thickness of the metal film are all shown to be of importance when discussing the mechanism for Nanoscale Island formation under high fluence irradiation. It is postulated that the resulting nanoparticle size distribution is influenced by the surface roughness of the initial film and the Rayleigh instability criterion. The results obtained are compared with simulations of the heat transfer through the film in order to further elucidate the mechanisms. The results are expected to be applicable to the laser induced melting of a large range of different materials, where poor wetting of substrate by the liquid phase is observed.
S J Henley - One of the best experts on this subject based on the ideXlab platform.
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pulsed laser induced Nanoscale Island formation in thin metal on oxide films
Physical Review B, 2005Co-Authors: S J Henley, J D Carey, S R P SilvaAbstract:he mechanisms controlling the nanostructuring of thin metal-on-oxide films by nanosecond pulsed excimer lasers are investigated. When permitted by the interfacial energetics, the breakup of the metal film into Nanoscale Islands is observed. A range of metals (Au, Ag, Mo, Ni, Ti, and Zn) with differing physical and thermodynamic properties, and differing tendencies for oxide formation, are investigated. The nature of the interfacial metal-substrate interaction, the thermal conductivity of the substrate, and the initial thickness of the metal film are all shown to be of importance when discussing the mechanism for Nanoscale Island formation under high fluence irradiation. It is postulated that the resulting nanoparticle size distribution is influenced by the surface roughness of the initial film and the Rayleigh instability criterion. The results obtained are compared with simulations of the heat transfer through the film in order to further elucidate the mechanisms. The results are expected to be applicable to the laser induced melting of a large range of different materials, where poor wetting of substrate by the liquid phase is observed.
Costas P Grigoropoulos - One of the best experts on this subject based on the ideXlab platform.
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nanosecond laser induce size controllable sige Islands with high ge composition large aspect ratio and defect free characteristics
Materials Letters, 2018Co-Authors: Shihao Huang, Letian Wang, Meng Shi, Songyan Chen, Costas P GrigoropoulosAbstract:Abstract In the present work, laser-induced directed dewetting (LIDD) of amorphous germanium thin films generates single crystalline SiGe Islands on Si substrate. Furthermore, SiGe Islands with a high aspect ratio of 1.06 are prepared by pulse laser irradiation. Variation of the nanosecond heating laser’s pulse fluence enables modulation of the Nanoscale Island size, and the diameter of Islands can be selected in the range of 40 nm–150 nm.
