Laser annealing of silicon clusters

Maruyama, Shigeo; Anderson, L. R.; Smalley, R. E.

doi:10.1063/1.459656

Cited by 68 publications

(28 citation statements)

References 9 publications

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“…In the high-resolution mobility experiments more than two isomers are clearly resolved for many cluster sizes. The existence of multiple isomers in this size regime is also suggested by previous mobility and chemical reactivity experiments [7][8][9][10].…”

Section: Introductionmentioning

confidence: 55%

Shape transition of medium‐sized neutral silicon clusters

Sieck¹,

Frauenheim

Jackson

2003

Physica Status Solidi (b)

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Addressing the shape transition of silicon clusters, indicated by mobility experiments on silicon cluster cations with 24 to 30 atoms, we investigate the structure of low energy neutral silicon clusters with 25, 29, and 35 atoms within a density-functional based tight-binding approach. Since there is strong evidence for several nearly degenerate low-energy isomers for clusters of this size, we perform an extensive, but limited global search with Simulated Annealing and statistically analyze for each cluster size the 100 clusters with the lowest energy. We find different dominant shapes in the set of low energy clusters for each size. For neutral silicon clusters with 25 atoms, both prolate and spherical structures with low cohesive energies exist. For clusters containing 29 or 35 atoms, the low-energy isomers exhibit a spherical shape. For each cluster size several stable isomers with similar shapes, and hence similar mobilities, but different bonding patterns exist. The most stable 25 atom cluster resulting from our global search has the lowest energy within DFT-GGA known so far. Finally, we investigate the transition to diamond-like bonding patterns expected for larger silicon clusters. Clusters with up to 239 atoms resemble amorphous silicon rather than the diamond structure and contain several highly coordinated atoms.

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Section: Introductionmentioning

confidence: 55%

Shape transition of medium‐sized neutral silicon clusters

Sieck¹,

Frauenheim

Jackson

2003

Physica Status Solidi (b)

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“…By use of these features, Freiser et al have performed photodissociation experiments on a number of heteronuclear metal dimers [12]. Laser irradiation of stored cluster ions has also been used by Smalley et al to anneal silicon clusters [13] and for photodissociation [14] and thermionic emission [15] studies of fullerenes.…”

Section: Introductionmentioning

confidence: 97%

Photo fragmentation of metal clusters stored in a penning trap

Walther

Becker

Dietrich

et al. 1996

Z Phys D - Atoms, Molecules and Clusters

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Photo fragmentation studies of stored mass selected metal cluster ions of a large size range are reported. The experimental method and the data evaluation are described in detail. Gold cluster ions were produced by laser vaporization and stored in a Penning trap. After size selection they were electronically excited by irradiation with a pulsed laser beam. Relaxation by evaporation of neutral atoms and dimers was observed as a function of photon energy. From these data upper and lower limits for dissociation energies are determined for Au> L (n"3 to 23).

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“…When, two door electrodes further restrict the longitudinal motion of ions, the cluster ions are completely trapped in the ICR cell for a few minutes. We can irradiate laser to the trapped cluster or let the chemical reaction in the cell [Maruyama et al (1990B), Maruyama et al (1991)]. The schematics of the whole apparatus are shown in of id 84 mm which penetrated the homogeneous 6 Tesla superconducting magnet commercially available for NMR.…”

Section: Ft-icr Mass Spectroscopymentioning

confidence: 99%

“…The 'back' door was always kept typically at +10 V. Then, cluster ions which had enough translational energy to climb up the screen door but smaller enough so that reflected by the back door would be trapped in the ICR cell. An example of the decelerator operation is demonstrated in Figure 6 for silicon clusters, which have no specific mass distribution as carbon [Maruyama et al (1990A), Maruyama et al (1990B)]. A silicon wafer cut to a disk was installed in the cluster beam source.…”

Section: Cluster Beam Source and Direct Injectionmentioning

confidence: 99%

“…Mass spectra of metalcarbon binary clusters are very complicated and we needed to implement a new FT-ICR (Fourier transform ion cyclotron resonance) spectrometer with extremely high mass-resolution. As our previous version at Rice University [Maruyama et al (1990A), Maruyama et al (1990B), Maruyama et al (1991)], a laser-vaporization supersonic-expansion cluster beam source (Maruyama et al, 1997) was directly connected to the FT-ICR spectrometer. In this paper, the implementation of this new spectrometer with the cluster source is discussed together with the preliminary studies of pure-carbon and metal-carbon binary clusters.…”

Section: Introductionmentioning

confidence: 99%

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FT-ICR Studies of Laser Desorbed Carbon Clusters.

Maruyama

Yoshida²,

Kohno³

1999

Trans.JSME, Ser.B

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Atomic and molecular clusters are being recognized as playing an important role in the thin-film deposition process and phase-change phenomena. Furthermore, small clusters are the most adequate system for the verification of quantum molecular dynamics calculations such as the interference of light and matter. Hence, experimental treatments of such atomic and molecular clusters are now desired. In order to examine such clusters, we have implemented a Fourier transform ion cyclotron resonance (FT-ICR) spectrometer directly connected to a laser-vaporization supersonicexpansion cluster beam source.The heart of the FT-ICR spectrometer was made of ICR cell cylinder centered in a strong homogeneous magnetic field of a 6 Tesla superconducting magnet. The atomic cluster beam was generated outside of magnetic field by the laser vaporization of a solid sample disk, followed by cooling with supersonic expansion of pulsed helium gas. The ionized cluster was carried by helium gas and directly injected to the magnetic field. By measuring the ion-cyclotron frequency, which was inversely proportional to the ion mass, a very highresolution mass spectrum can be obtained.The high mass-resolution was demonstrated for positive mass spectra of silicon, carbon, and metal-carbon binary clusters and negative mass spectra of metal-carbon binary clusters. For bare carbon positive clusters, we found the special condition where the odd-numbered clusters were observed in the range of C 30 to C 50 and the continuous change to C 60 -dominant condition and 'normal' even-numbered distribution.An example of mass spectrum measured by the directinjection FT-ICR apparatus is shown in Figure A Copyright © 1999 by ASME 2Magnetic field f :Ion cyclotron resonance frequency m :Mass of cluster ion q :Charge of cluster ion r :Radius of cyclotron motion v : Velocity INTRODUCTIONAtomic and molecular clusters are being recognized as playing an important role in the thin-film deposition process and phase-change phenomena. Furthermore, small clusters are the most adequate system for the verification of quantum molecular dynamics calculations such as the interference of light and matter, since a cluster is the unique small atomic system with a physically clear boundary condition. Hence, experimental treatments of such atomic and molecular clusters are now desired.Studies of clusters have another possibility leading to the discovery of new materials such as fullerene. Fullerene was first discovered in the mass-spectroscopic study by Kroto et al. (1985). Then, in 1990 the macroscopic generation by arcdischarge technique [Krätschmer et al. (1990), Haufler et al. (1991)] was introduced. Furthermore, higher fullerene [Kikuchi et al. (1992)], metal-containing fullerene , Kikuchi et al. (1993), Takata et al. (1995] and nanotube [Iijima (1991), Thess et al. (1996)] were also generated by the similar technique. Even though the generation of fullerene is now possible by the arc-discharge technique or laser-oven technique ), Wakabayashi et al. (1997], the formation ...

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Laser annealing of silicon clusters

Cited by 68 publications

References 9 publications

Shape transition of medium‐sized neutral silicon clusters

Shape transition of medium‐sized neutral silicon clusters

Photo fragmentation of metal clusters stored in a penning trap

FT-ICR Studies of Laser Desorbed Carbon Clusters.

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