Laser induced effects on ZnO targets upon ablation at 266 and 308 nm wavelengths
- Instituto de Quimica Fisica 'Rocasolano', C.S.I.C. Serrano 119, 28006 Madrid (Spain)
- Instituto de Estructura de la Materia, C.S.I.C. Serrano 121, 28006 Madrid (Spain)
The development of structural changes in ZnO targets, upon laser irradiation at the wavelengths of 266 and 308 nm, is studied by Raman spectroscopy. At the wavelength of 308 nm, oxygen vacancies are found to develop monotonically with increasing laser intensity. At 266 nm, a structural change in the irradiated ZnO targets, possibly related to nanostructuring, is observed above the laser fluence of 0.45 J cm{sup -2}. The different natures of the laser target interaction processes taking place at both wavelengths are investigated through the characterization of the composition and energy distribution of the species ejected in the ablation. The energy of the neutral Zn and Zn{sub 2} present in the ablation at 308 nm shows a smooth dependence on laser fluence which is consistent with the observed smooth development of oxygen vacancies. At 266 nm, the average kinetic energy of the ejected fragments is higher than at 308 nm and changes abruptly with the ablating laser fluence, consistently with the presence of a fluence threshold above which structural transform is observed at this wavelength. The plume shows the same neutral composition (Zn, ZnO, and Zn{sub 2}) at both wavelengths but the dependence on fluence of the ratio of neutral atomic Zn to the dimer Zn{sub 2} shows significant differences. From the latter, different temperature regimes can be inferred in the plume generated at both wavelengths. At 266 nm the cationic composition of the plume is mainly stoichiometric whereas at 308 nm ZnO{sub 2(3)}H{sub 2(1)}{sup +} cations have the highest intensity.
- OSTI ID:
- 21137406
- Journal Information:
- Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 2 Vol. 104; ISSN JAPIAU; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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