Pulsed laser positive ion desorption from a model hydrated inorganic crystal (CaHPO4·2H2O) at 248 nm

Dawes, M. L.; Langford, S. C.; Dickinson, J. T.

doi:10.1016/s0169-4332(97)00614-4

Cited by 10 publications

(9 citation statements)

References 14 publications

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“…In prior work with single-crystal MgO, 2,21 single-crystal NaNO 3 and CaCO 3 , 22 single-crystal CaHPO 4 Á2H 2 O (brushite), 7 and amorphous (fused) silica, 6 we found that mechanical treatments (e.g., abrasion, indentation) increase the PIE intensities. These materials are all good insulators.…”

Section: Effect Of Mechanical Surface Treatmentsmentioning

confidence: 64%

“…We have previously shown that laser-induced ion emission from wide bandgap insulators originates from surface defect sites where a positive ion is sorbed on top of a surface electron trap. [1][2][3][4][5][6][7][8][9] We suggest that the corresponding defect configuration for semiconducting ZnO is a zinc ion sorbed on top of a surface oxygen vacancy. When the electron trap is photoionized by the laser, the electrostatic force on the sorbed positive ion changes sign and the ion is ejected with significant kinetic energy.…”

Section: Resultsmentioning

confidence: 87%

“…This reflects an intermediate case between metals, where direct ion emission is strongly hindered by the high probability of neutralization, 17 and insulators, where neutralization is rare and intense positive ion emissions are often observed. [1][2][3][4][5][6][7][8][9] We have observed Zn þ and O þ emission from singlecrystal Zn ð10 10Þ surfaces exposed to 193-nm excimer laser radiation. At fluences below about 150 mJ/cm 2 , Zn þ is the dominant positive ion.…”

Section: Discussionmentioning

confidence: 99%

“…Examples include MgO, 1-3 a number of alkali halides, 4,5 fused silica, 6 and more complex oxides. [7][8][9] In each case, the photon energy is well below the material's bandgap, in which case photon absorption is defect-mediated. We have shown that these emissions are due to the electrostatic ejection of ions that are sorbed atop photoionized surface electron traps.…”

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confidence: 99%

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The interaction of 193-nm excimer laser irradiation with single-crystal zinc oxide: Positive ion emission

Khan

Langford

Dickinson

et al. 2012

Journal of Applied Physics

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We examine UV laser-induced ion emission from a wide bandgap semiconductor, single-crystal ZnO, at fluences well below both the damage threshold and plasma formation. At fluences below 200 mJ/cm2, we observe only Zn+, and the Zn+ intensity decreases monotonically during exposure. At higher fluences, after an initial decrease, the emission is sustained; in addition O+ and O2+ are observed. We explain: how Zn ions of several eV in energy can be produced on the surface of a semiconductor, how sustained emission can be maintained, and the origin of an anomalous emission of slow Zn+ ions — the latter is shown to arise from photoionization of atomic Zn, also emitted by this radiation.

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Section: Effect Of Mechanical Surface Treatmentsmentioning

confidence: 64%

Section: Resultsmentioning

confidence: 87%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

The interaction of 193-nm excimer laser irradiation with single-crystal zinc oxide: Positive ion emission

Khan

Langford

Dickinson

et al. 2012

Journal of Applied Physics

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“…[9][10][11][12][13][14][15][16][17][18][19] In the presence of an adsorbed ion, the energy require to photoionize the electron trap can exceed ten eV, well above the photon energy. However, photoionization of nearby electron traps can lower the ion binding energy and provide nearby empty electron traps.…”

Section: Discussionmentioning

confidence: 99%

Ion emission from fused silica under 157-nm excimer laser irradiation at fluences below plasma formation threshold: the role of surface defects

2006

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At fluences well below the threshold for plasma formation, we have characterized the direct desorption of atomic ions from fused silica surfaces during 157-nm irradiation by time-resolved mass spectroscopy. The principal ions are Si + and O + . The emission intensities are dramatically increased by treatments that increase the density of surface defects. Molecular dynamics simulations of the silica surface suggest that silicon ions bound at surface oxygen vacancies (analogous to E' centers) provide suitable configurations for the emission of Si + . We propose that emission is best understood in terms of a hybrid mechanism involving both antibonding chemical forces (MenzelGomer-Redhead model) and repulsive electrostatic forces on the adsorbed ion after laser excitation of the underlying defect.

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The effect of water vapor and bulk temperature on positive ion emission from wide bandgap single crystals during exposure to 248 nm excimer laser radiation

Nwe

Langford

Dickinson

2002

Applied Surface Science

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Pulsed laser positive ion desorption from a model hydrated inorganic crystal (CaHPO4·2H2O) at 248 nm

Cited by 10 publications

References 14 publications

The interaction of 193-nm excimer laser irradiation with single-crystal zinc oxide: Positive ion emission

The interaction of 193-nm excimer laser irradiation with single-crystal zinc oxide: Positive ion emission

Ion emission from fused silica under 157-nm excimer laser irradiation at fluences below plasma formation threshold: the role of surface defects

The effect of water vapor and bulk temperature on positive ion emission from wide bandgap single crystals during exposure to 248 nm excimer laser radiation

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