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1.
Annealing of radiation induced defects in p-type germanium was studied by measuring Hall coefficient and conductivity. The dopant was gallium or indium. It was concluded that the annealing stage between 80° and 140°K is caused by migration of the vacancy to the sink of an impurity atom. In this stage the vacancy migrates to a substitutional impurity atom and makes an association. The activation energy of the stage was found tO be 0.1 ev ad it is regarded to be that of the vacancy migration. The model for the annealing stage which occurs in the range 220 to 270°K is proposed as follows: An interstitial impurity atom migrates to a substitutional impurity atom and makes an association. From the activation energy of the stage, the migration energy of the interstitial impurity atom was concluded to be about 0.4 eV for gallium and 0.7 eV for indium atoms. 相似文献
2.
S.F. Cheng 《Surface science》2006,600(14):2924-2927
Ordered and disordered InGaP(0 0 1) films were grown by metalorganic vapor-phase epitaxy and studied by low energy electron diffraction, reflectance difference spectroscopy, and X-ray photoemission spectroscopy. Both alloy surfaces were covered with a monolayer of buckled phosphorus dimers, where half of the phosphorus atoms were terminated with hydrogen. Ordered InGaP(0 0 1) appeared indium rich, and exhibited a reflectance difference spectrum like that of InP(0 0 1). These results support a model whereby the strain energy on the ordered InGaP surface is reduced by aligning the group III atoms in alternating [1 1 0] rows, with the indium and gallium bonding to the buckled-down and buckled-up phosphorus atoms, respectively. 相似文献
3.
We have theoretically and experimentally investigated the focusing properties of a detuned pulsed standing wave onto a beam
of neutral atoms. In close analogy to the continuous-wave situation the dipole force leads to a periodic focusing of atoms
with a period of λ/2, provided an adiabatic condition is fulfilled. Pulsed laser light is conveniently converted to short
wavelengths and hence offers advantages in the application of atom lithography with elements of technological interest having
blue or UV resonance lines.
Received: 6 October 1999 / Revised version: 3 February 2000 / Published online: 5 April 2000 相似文献
4.
We present details for the laser manipulation of group III atoms, specifically aluminum, gallium, and indium. The practical
considerations of accomplishing this manipulation are discussed and alternative schemes are presented for each species. The
possibility of using such an optical technique for composition modulation during semiconductor growth for the fabrication
of quantum wire and quantum dot structures is also discussed.
Received: 29 September 1999 / Published online: 5 April 2000 相似文献
5.
Atom lithography with a cold, metastable neon beam 总被引:1,自引:0,他引:1
P. Engels S. Salewski H. Levsen K. Sengstock W. Ertmer 《Applied physics. B, Lasers and optics》1999,69(5-6):407-412
We study different aspects of atom lithography with metastable neon atoms. Proximity printing of stencil masks is used to
test suitable resists that are sensitive to the internal energy of the atoms, including dodecanethiols on gold and octadecyltrichlorosilanes
grown on a SiO2 surface. As an example of patterning the atomic beam with laser light, we create parallel line structures on the surface
with a periodicity of half the laser wavelength by locally de-exciting the atoms in a standing quenching wave.
Received: 29 June 1999 / Revised version: 30 August 1999 / Published online: 10 November 1999 相似文献
6.
G. Nagarajan 《Czechoslovak Journal of Physics》1966,16(2):157-166
The Cyvin method, utilizing symmetry coordinates, has been employed here to compute the mean-square amplitude quantities, generalized mean-square amplitudes (mean-square parallel amplitudes, mean-square perpendicular amplitudes and mean cross products) and mean amplitudes of vibration for the bonded as well as non-bonded atom pairs at the temperaturesT=298°K andT=500°K for the tetrahedral tetrahalogeno complexes of zinc, cadmium, gallium, indium, thallium and arsenic. The non-linear behaviour of the mean amplitudes of vibration in terms of the electronegativities of the central atoms has been discussed, followed by a discussion on the replacement of peripheral atoms. 相似文献
7.
B. Xu B. C. Pan 《The European Physical Journal B - Condensed Matter and Complex Systems》2010,73(3):413-416
The adsorption of single gallium atoms on the inner walls of
single-walled carbon nanotubes with hydrogen/oxygen-saturated
monovacancies are studied by using the density functional theory
method. When the monovacancy is saturated by the hydrogen or
oxygen atom, the gallium atom prefers to adsorb on the top of the
center of a pentagon ring, and the binding energy between the
gallium atom and carbon nanotube is significantly lower as compared
to the case with a pure monovacancy. In addition, the results of the
density of states show that the states originating from the adsorbed
gallium atoms shift toward lower energy when the carbon atoms with
dangling bonds are saturated by hydrogen or oxygen atoms. Meanwhile,
these states have no contribution to the states near the Fermi
levels. 相似文献
8.
T. Meijer J. P. Beardmore C. G. C. H. M. Fabrie J. P. van Lieshout R. P. M. J. W. Notermans R. T. Sang E. J. D. Vredenbregt K. A. H. van Leeuwen 《Applied physics. B, Lasers and optics》2011,105(4):703-713
Atom lithography uses standing wave light fields as arrays of lenses to focus neutral atom beams into line patterns on a substrate.
Laser cooled atom beams are commonly used, but an atom beam source with a small opening placed at a large distance from a
substrate creates atom beams which are locally geometrically collimated on the substrate. These beams have local offset angles
with respect to the substrate. We show that this affects the height, width, shape, and position of the created structures.
We find that simulated effects are partially obscured in experiments by substrate-dependent diffusion of atoms, while scattering
and interference just above the substrate limit the quality of the standing wave lens. We find that in atom lithography without
laser cooling the atom beam source geometry is imaged onto the substrate by the standing wave lens. We therefore propose using
structured atom beam sources to image more complex patterns on subwavelength scales in a massively parallel way. 相似文献
9.
Takahiro Ishikawa Masaya Nomura Kuniko Kato Naoshi Suzuki Katsuya Shimizu Hiroyoshi Itoh 《高压研究》2013,33(1):152-157
The superconductivity of gold–indium alloys has been investigated using first-principles calculations based on the density functional theory. At ambient pressure, the calculated superconducting transition temperature (T c) is 0.04 μ K in pure gold, but T c dramatically increases by substituting indium atoms for gold atoms. The gold–indium alloy having 12.5 atomic percent indium (Au0.875In0.125) shows T c of 0.1 K, and Au0.75In0.25 marks 1.7 K. The dramatic increase in T c owing to the alloying effect is caused by the enhancement of the electron–phonon coupling. The superconductivity of gold is predicted to be drastically weakened with increasing pressure and virtually disappear at 10 GPa, but it continues up to at least 30 GPa by the inclusion of indium atoms. 相似文献
10.
A. M. Khanbekyan A. A. Khanbekyan 《Journal of Contemporary Physics (Armenian Academy of Sciences)》2018,53(3):222-226
The process of interaction of gallium atom vapors with the walls of a quartz cell was spectroscopically investigated. It has been shown that at high temperature (~1080°C) the process of diffusion of gallium atoms into the walls of the cell prevents to reach the densities of the metal vapors in the cell corresponding to the table values for given temperature. After saturation the cell walls by the metal atoms, the density of metal vapor in the volume of the cell increases. 相似文献
11.
We have created periodic nanoscale structures in a gold substrate with a lithography process using metastable triplet helium atoms that damage a hydrophobic resist layer on top of the substrate. A beam of metastable helium atoms is transversely collimated and guided through an intense standing-wave light field. Compared to commonly used low-power optical masks, a high-power light field (saturation parameter of 107) increases the confinement of the atoms in the standing wave considerably, and makes the alignment of the experimental setup less critical. Due to the high internal energy of the metastable helium atoms (20 eV), a dose of only one atom per resist molecule is required. With an exposure time of only eight minutes, parallel lines with a separation of 542 nm and a width of 100 nm (one-eleventh of the wavelength used for the optical mask) are created.PACS 32.80.Lg; 39.25.+k; 81.16.Nd 相似文献
12.
R.R. Chaustowski V.Y.F. Leung K.G.H. Baldwin 《Applied physics. B, Lasers and optics》2007,86(3):491-496
Sources of rare gas atoms in excited metastable states have been used to expose photoresist-coated substrates to demonstrate
atom lithography. These thermal atomic beams are usually created by discharge sources that also produce copious amounts of
UV radiation. The UV radiation simultaneously illuminates the substrate and may play a complementary role in altering the
photoresist together with the metastable atoms. In the experiments reported here, we have isolated the UV component using
a magnetic hexapole lens to focus a thermal beam of metastable helium atoms around a fiducial mask that blocks the UV light.
This creates an atom lithography exposure that is the result of illumination by the atoms alone. We have also modelled the
performance of the magnetic hexapole lens as a potentially useful device for atom lithography.
PACS 39.25.+k; 81.16.Nd 相似文献
13.
We report on the efficient generation of cold rubidium atoms as a potential coherent atom source for atom lithography. We
successfully trapped and cooled 2.6 × 108 atoms in 5 s with a conventional magneto-optical trap simply by enlarging the diameter of the laser beam to 20 mm. The size
of the laser-cooled atom cloud was measured to be 10 × 7 × 7 mm3. The number of trapped atoms was approximately 10 times as large as that of previous typical results, while the loading time
of atoms remained the same. 相似文献
14.
This paper concentrates on the possible segregation of indium and gallium and competitive segregation of gallium and indium at atomically flat parallel {111}-oriented Cu-MnO interfaces. The segregation of gallium at Cu-MnO interfaces after introduction of gallium in the copper matrix of internally oxidized Cu-1 at.% Mn could be hardly detected with energy-dispersive spectrometry in a field emission gun transmission electron microscope. After a heat treatment to dissolve indium in the copper matrix, gallium has a weak tendency to segregate, that is 2.5 at.% Ga per monolayer at the interface compared with 2 at.% in the copper matrix. The striking result is that this gallium segregation is observable because it does not occur at the metal side of the interface but in the first two monolayers at the oxide side. Using the same heat treatment as for introducing indium in the sample, but without indium present, gallium segregates strongly at the oxide side of the Cu-MnO interface with a concentration of about 14.3 at.% in each monolayer of the two. In contrast, the presence of gallium has no influence on the segregation of indium towards Cu-MnO interfaces, because the outermost monolayer at the metal side of the interface contains 17.6 at.% In, that is similar to previously found results. This leads to the intriguing conclusions, firstly, that, in contrast with antimony and indium, gallium segregates at the oxide side of the interface and, secondly, that the presence of indium strongly hampers gallium segregation. The results from analytical transmission electron microscopy on gallium segregation are supported by high-resolution transmission electron microscopy observations. 相似文献
15.
We present a detailed model describing the effects of
wire corrugation on the trapping potential experienced by a cloud
of atoms above a current carrying micro wire. We calculate the
distortion of the current distribution due to corrugation and then
derive the corresponding roughness in the magnetic field above the
wire. Scaling laws are derived for the roughness as a function of
height above a ribbon shaped wire. We also present experimental
data on micro wire traps using cold atoms which complement some
previously published measurements [CITE] and which
demonstrate that wire corrugation can satisfactorily explain our
observations of atom cloud fragmentation above electroplated gold
wires. Finally, we present measurements of the corrugation of new
wires fabricated by electron beam lithography and evaporation of
gold. These wires appear to be substantially smoother than
electroplated wires. 相似文献
16.
Multimillion Atom Molecular Dynamics Simulations of Nanostructures on Parallel Computers 总被引:2,自引:0,他引:2
Vashishta Priya Kalia Rajiv K. Nakano Aiichiro 《Journal of nanoparticle research》2003,5(1-2):119-135
Scalable space–time multiresolution algorithms implemented on massively parallel computers enable large-scale molecular dynamics (MD) simulations involving up to a billion atoms. Multimillion atom MD simulations are performed to study critical issues in the area of structural and dynamical correlations in nanostructures. Our simulation research is focused on a few semiconductor, ceramic, and metallic nanostructures. These nanostructures systems include: nanometer-scale stress patterns in silicon/silicon nitride nanopixels; self-limiting growth and critical lateral sizes in gallium arsenide/indium arsenide nanomesas; structural transformation in colloidal semiconductor nanocrystals; nanoindentation of crystalline and amorphous silicon nitride films; and dynamics of oxidation of metallic aluminum nanoparticles. 相似文献
17.
A.V. Samartsev 《Applied Surface Science》2006,252(19):6474-6477
The emission of neutral and charged atoms and clusters from a polycrystalline indium surface under bombardment with 5 and 10 keV Au, Au2, Au3 and Au5 projectiles was investigated. Single photon laser postionization was utilized for the detection of sputtered neutral particles. Secondary ions were detected without the laser under otherwise exactly the same experimental conditions. The relative cluster yields were found to be enhanced under polyatomic projectile bombardment, more so the larger the number of atoms in the sputtered cluster. The ionization probability strongly increases with increasing cluster size, but is essentially independent of the projectile impact energy. At a fixed impact energy, the ionization probability of sputtered monomers was found to decrease with increasing number of constituent gold atoms per projectile, but there was no detectable effect for sputtered dimers and larger clusters. 相似文献
18.
用反射式高能电子衍射仪首次观察到在Si(111)面上的一部分铟吸附原子在直流电场下,沿电场方向发生迁移的现象——表面电致迁移。根据所观察到的表面电致迁移过程,可以把吸附在Si(111)面上的铟原子的结合状态分成两类:紧靠着硅表面的一个单原子层铟与硅表面结合牢固,几乎不受电场影响,称为紧固层;在紧固层以上的铟层易受电场影响而发生表面电致迁移,称为迁移层。从铟原子的表面电致迁移率与温度的关系,求得表面质量迁移的激活能为0.43eV。用表面电导测量研究了In-Si(111)界面形成过程中的电荷转移现象。结果表明,吸附在硅表面的铟原子形成表面深施主能级。导致表面电致迁移的力是离化了的铟原子在电场中所受到的库仑力。
关键词: 相似文献
19.
以苯基荧光酮沉淀捕集溶液中的痕量镓、锗、钼和铟,用石墨炉原子吸收法进行测定。研究了溶液酸度、苯基荧光酮(PF)用量、陈化时间、溶液体积以及共存元素的影响。最佳条件分别为:Ga(Ⅲ):500 mL pH≈2溶液中加入10.00 mg·mL-1 PF 2.00 mL,陈化4h;Ge(Ⅳ):500 mL pH≈2溶液中加入10.00 mg·mL-1 PF 4.00 mL,陈化10 h;Mo(Ⅴ):1 000 mL pH≈3溶液中加入10.00 mg·mL-1 PF 3.00 mL,陈化6 h;In(Ⅲ):100 mL pH≈5溶液中加入10.00 mg·mL-1 PF 4.00 mL,陈化10 h。实验显示,苯基荧光酮沉淀对痕量镓、锗、钼和铟的捕集过程以后沉淀为主。方法检出限(3s):镓0.12 ng·mL-1, 锗0.30 ng·mL-1, 钼0.046 ng·mL-1,铟2.7 ng·mL-1。该方法成功地用于石墨炉原子吸收测定水溶液、国家地质标准物质和锌精矿中痕量镓、锗、钼和铟。 相似文献