Spatial analysis of band emission from laser produced plasma

Harilal, S. S.; Issac, R. C.; Bindhu, C. V.; Nampoori, V. P. N.; Vallabhan, C. P. G.

doi:10.1088/0963-0252/6/3/008

Cited by 13 publications

(11 citation statements)

References 35 publications

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“…In contrast, at the high intensity regime, a dimerization reaction at atomic level to recombine the carbon atoms dominates. [6][7][8][9] A valuable diagnostic tool to infer the predominance of atomization or fragmentation reactions in the plasma is the ratio of CN to C 2 intensities. This fraction quantifies the seeding of the plasma with radicals and fragments and is thus connected with the extra stability resulting from the arrangement of π electrons associated with the p orbitals of the cyclic structure.…”

Section: Emissions Influenced By Aromatic Structuresmentioning

confidence: 99%

“…3 Particularly, a considerable number of investigations have been made on graphite plasmas to reveal the spatial and temporal distribution of different species ejected during ablation. [4][5][6][7] Studies on organic plasmas in various atmospheres 8 at a range of pressures, [9][10][11][12] using different laser wavelengths, 13 at diverse laser fluence regimes, have provided valuable information in the context of pulsed laser deposition, well known for its capabilities for film synthesis as well as for the assembling of novel materials such as single-walled carbon nanotubes. 14 Progress in laser ablation together with monitoring of optical emissions has emerged as a valuable method for characterization of laser-induced organic plasmas.…”

Section: ■ Introductionmentioning

confidence: 99%

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Sensing Signatures Mediated by Chemical Structure of Molecular Solids in Laser-Induced Plasmas

2015

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Laser ablation of organic compounds has been investigated for almost 30 years now, either in the framework of pulse laser deposition for the assembling of new materials or in the context of chemical sensing. Various monitoring techniques such as atomic and molecular fluorescence, time-of-flight mass spectrometry, and optical emission spectroscopy have been used for plasma diagnostics in an attempt to understand the spectral signature and potential origin of gas-phase ions and fragments from organic plasmas. Photochemical and photophysical processes occurring within these systems are generally much more complex than those suggested by observation of optical emission features. Together with laser ablation parameters, the structural and chemical-physical properties of molecules seem to be closely tied to the observed phenomena. The present manuscript, for the first time, discusses the role of molecular structure in the optical emission of organic plasmas. Factors altering the electronic distribution within the organic molecule have been found to have a direct impact on its ensuing optical emissions. The electron structure of an organic molecule, resulting from the presence, nature, and position of its atoms, governs the breakage of the molecule and, as a result, determines the extent of atomization and fragmentation that has proved to directly impact the emissions of CN radicals and C2 dimers. Particular properties of the molecule respond more positively depending on the laser irradiation wavelength, thereby redirecting the ablation process through photochemical or photothermal decomposition pathways. It is of paramount significance for chemical identification purposes how, despite the large energy stored and dissipated by the plasma and the considerable number of transient species formed, the emissions observed never lose sight of the original molecule.

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Section: Emissions Influenced By Aromatic Structuresmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Sensing Signatures Mediated by Chemical Structure of Molecular Solids in Laser-Induced Plasmas

2015

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“…If a plasma is in LTE, the excited state population can be related to the temperature of the plasma and the energy of the state through the Boltzmann equation, eq. 3.1 [54] These plasmas are typically characterised with high temperatures, pressures and number densities of species. Whether PLD plasmas are in LTE is subject of debate.…”

Section: Local Thermodynamic Equilibriummentioning

confidence: 99%

Stoichiometry control in oxide thin films by pulsed laser deposition

Groenen

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Cover image: Reflection High Energy Electron Diffraction patterns of SrTiO 3 thin films on SrTiO 3 substrates grown with pulsed laser deposition at various partial oxygen background gas pressure conditions. The colorscale and the level of detail of the image are manipulated.The research described in this thesis was carried out within the Inorganic Materials Science group, Department of Science and Technology and the MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands. This research is supported by the Dutch Technology Foundation STW, which is part of the Netherlands Organization for Scientific Research (NWO) and partly funded by the Ministry of Economic Affairs (project number 10760). Chapter 1 Stoichiometry control in oxide thin films IntroductionIn 1959 Richard Feynman for the first time discussed the synthesis of materials via manipulation of single atoms in his famous talk 'There's Plenty of Room at the Bottom'. 1 Since then, the advances and achievements in the field of nanotechnology have lead to functionalised materials, devices and technology with increasingly smaller integrated circuits and denser data storage. The term nanotechnology itself was first used by Norio Taniguchi, professor of Tokyo University of Science in 1974, to describe processes such as thin film deposition exhibiting control on the order of a nanometer. [1] His definition of nanotechnology, Nano-technology mainly consists of the processing of separation, consolidation, and deformation of materials by one atom or one molecule, still stands today and romantically summarises the essence of materials science and engineering at nanoscale dimensions. Advances in fabrication processes and characterisation techniques have made it possible to synthesise, characterise and manipulate material at the atomic scale. At these dimensions, quantum effects dominate the properties of materials such that intrinsic material bulk properties are altered or lost and new phenomena and properties can emerge. This creates new pathways and possibilities for new applications. A good example is the giant magnetoresistance effect, widely applied in magnetic field sensors in hard disk drives and all sorts of sensors. A highly interesting class of materials are complex metal oxides, for their rich variety of interesting physical properties such as ferroelectricity, ferromagnetism and superconductivity. A widely investigated sub-group within the complex metal oxides are the perovskite metal oxides. The term 'perovskite' originates from the discovery of the calcium titanium oxide (CaTiO 3 ) mineral in 1839, but is nowadays used to describe the family of crystals with an ABO 3 stoichiometry. The unit cell of perovskites has rare-earth or metal A and B cations and six oxygen atoms, forming a BO 6 oxygen octahedra in the centre of the cubic with the A cation in its corners.The properties of (perovskite) complex metal oxides are highly sensitive to slight deviation from the ideal crystal stoichiometry. Therefore, a gen...

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“…In magnetron discharges, excitation by electronic collisions prevails, the electron density ne is generally between 10 l~ and 1011 cm -3 and electron temperature Te ~ (0.5-4)eV [12][13][14]. While in laser plasma, at the target, ne reaches 101Scm -3 and Te ~ 2.5eV [15]. The plasma diagnostics can be easily realized using optical emission spectroscopy (OES).…”

Section: Introductionmentioning

confidence: 99%

Study of the plasmas produced during the deposition of TiC/SiC thin films in a hybrid magnetron-laser system

et al. 2006

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Time-and spatially-resolved optical emission spectroscopy was performed to characterize the plasma produced in a hybrid magnetron-sputtering-laser deposition system, which is used for TiC or SiC thin films preparation. A graphite target was ablated by a KrF excimer laser (A = 248 nm, v ---20 ns) and either Ti or Si targets were used for DC magnetron sputtering in argon ambient. Spectra were measured in the range 250-850 nm. The evolution of the spectra with varying magnetron powers (0-100 W) and argon pressures (0.3-10 Pa) was studied. Spectra of the plasmas produced by a) the magnetron alone, b) the ablation laser alone, and c) the magnetron and the ablation laser together, were recorded. Spectra (a) were dominated by Ar atoms and Ar + ions. Emission lines of Ti and Si were detected, when Ti target and Si target was used, respectively. Spectra (b) revealed emission of C, C +, C2, Ar, Ar +. Spectra (c) showed presence of all previously mentioned species and further of Ti + ions emission was detected. : 52.38.Mf, PACS

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Spatial analysis of band emission from laser produced plasma

Cited by 13 publications

References 35 publications

Sensing Signatures Mediated by Chemical Structure of Molecular Solids in Laser-Induced Plasmas

Sensing Signatures Mediated by Chemical Structure of Molecular Solids in Laser-Induced Plasmas

Stoichiometry control in oxide thin films by pulsed laser deposition

Study of the plasmas produced during the deposition of TiC/SiC thin films in a hybrid magnetron-laser system

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