Analysis of ion-bombarded and laser-irradiated surfaces of ZnS and Zn via two-photon high-resolution laser-induced fluorescence spectroscopy
Doppler-shifted two-photon laser-induced fluorescence spectroscopy (LFS) has been used for the first time to measure the velocity distributions of Zn atoms ejected by Ar/sup /plus// ion bombardment from both a Zn surface and a ZnS single crystal. Doppler-shifted spectroscopy in combination with time-of-flight, has also been employed to investigate Zn atoms ejected from a ZnS single crystal under irradiation by 308 nm photons (XeCl excimer laser). The absolute Zn sputtering yields from ion-bombarded and laser-irradiated ZnS samples were determined by comparison with LFS measurements of Zn atoms sputtered from pure Zn targets by Ar/sup /plus// ions since the absolute sputtering yield is known. For the Zn target the velocity distributions of the ion-induced sputtered Zn atoms were in good agreement with the Sigmund-Thompson distribution based on the known binding energy of 1.35 eV. On the other hand the velocity distribution of Zn atoms ion-sputtered from ZnS showed some deviation from the Sigmund-Thompson distribution and had a lower binding energy, /approximately/0.90 eV. The velocity distributions of the laser-ablated Zn atoms from ZnS were Maxwell-Boltzman in nature with characteristic temperatures increasing from 2000 to 9000 K at fluences of 20 and 80 mJ/cm/sup 2/, respectively. The absolute sputtering yield (Y) of Zn sputtered from ZnS was found to be Y /congruent/ 8.3 atoms/ion for ion sputtering and Y /congruent/ 10/sup /minus/6/ atoms/photon at a laser fluence of 30 mJ/cm/sup 2/ for laser ablation. High-resolution Doppler-shift techniques have been combined with TOF techniques. This promising combination permits unambiguous detection of prompt and delayed emission of ablated atoms, as well as the observation of possible molecular or cluster fragmentation. The results obtained indicate that no delayed emission is occurring and suggest the possibility of molecule or cluster emission from ZnS. 52 refs., 6 figs.
- Research Organization:
- Lawrence Livermore National Lab., CA (USA)
- DOE Contract Number:
- W-7405-ENG-48; W-31109-ENG-38
- OSTI ID:
- 6719553
- Report Number(s):
- UCRL-99509; CONF-881002-9; ON: DE88017015
- Resource Relation:
- Conference: 35. national vacuum symposium and 4th international laser science conference, Atlanta, GA, USA, 2 Oct 1988; Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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High-resolution multiphoton laser-induced fluorescence spectroscopy of zinc atoms ejected from laser-irradiated ZnS crystals
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ZINC
LASER RADIATION
ZINC SULFIDES
ARGON IONS
DOPPLER BROADENING
ELECTRONIC STRUCTURE
FLUORESCENCE SPECTROSCOPY
MONOCRYSTALS
PARTICLES
PHOTONS
SPECTRA
SPUTTERING
TIME-OF-FLIGHT METHOD
VELOCITY
CHALCOGENIDES
CHARGED PARTICLES
CRYSTALS
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ELEMENTS
EMISSION SPECTROSCOPY
INORGANIC PHOSPHORS
IONS
LINE BROADENING
MASSLESS PARTICLES
METALS
PHOSPHORS
RADIATIONS
SPECTROSCOPY
SULFIDES
SULFUR COMPOUNDS
ZINC COMPOUNDS
656003* - Condensed Matter Physics- Interactions between Beams & Condensed Matter- (1987-)