Role of electronic-excitation effects in the melting and ablation of laser-excited silicon
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| Title: | Role of electronic-excitation effects in the melting and ablation of laser-excited silicon |
|---|---|
| Authors: | Shokeen, Lalit1, Schelling, Patrick K. pschell@mail.ucf.edu |
| Source: | Computational Materials Science. Feb2013, Vol. 67, p316-328. 13p. |
| Subjects: | Silicon, Laser ablation, Electronic excitation, Temperature effect, Electron distribution, Phase transitions, Thermal analysis |
| Abstract: | Abstract: We present a model of laser–solid interactions in silicon based on a previously-developed interatomic potential for silicon where the parameters describing the interactions depend on the temperature of the electronic subsystem T e , which is directly related to the density of electron–hole pairs and hence the number of broken covalent bonds. For 25fs pulses, a wide range of fluence values are simulated resulting in heterogeneous melting, homogeneous melting, and ablation. The results presented here demonstrate that phase transitions can usually be described by ordinary thermal processes even when the electronic temperature T e is much greater than the lattice temperature T L during the transition. However, the evolution of the system and details of the phase transitions depend strongly on T e and corresponding density of broken bonds. Homogeneous melting appears to be an ordinary thermal phase transition, but occurring over very fast time scales (1–5ps) before T L reaches the ordinary melting temperature of silicon. For high enough laser fluence, homogeneous melting is followed by rapid expansion of the superheated liquid and ablation. Rapid expansion of the superheated liquid occurs partly due to high pressures generated by a high density of broken bonds. As a result of rapid expansion of the superheated liquid, the system is readily driven into the liquid–vapor coexistence region which initiates phase explosion. These results strongly indicate that phase explosion, generally thought of as an ordinary thermal process, can occur even under strong nonequilibrium conditions when T e ≫ T L . Thus, the results both for melting and ablation processes suggest that for many cases there is no clear separation between thermal and nonthermal processes. Instead, ordinary thermal mechanisms are found to apply when T e ≫ T L , with the high density of broken bonds playing an important role in the detailed evolution of the system. [Copyright &y& Elsevier] |
| Copyright of Computational Materials Science is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 83652553 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Role of electronic-excitation effects in the melting and ablation of laser-excited silicon – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Shokeen%2C+Lalit%22">Shokeen, Lalit</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Schelling%2C+Patrick+K%2E%22">Schelling, Patrick K.</searchLink><i> pschell@mail.ucf.edu</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Computational+Materials+Science%22">Computational Materials Science</searchLink>. Feb2013, Vol. 67, p316-328. 13p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Silicon%22">Silicon</searchLink><br /><searchLink fieldCode="DE" term="%22Laser+ablation%22">Laser ablation</searchLink><br /><searchLink fieldCode="DE" term="%22Electronic+excitation%22">Electronic excitation</searchLink><br /><searchLink fieldCode="DE" term="%22Temperature+effect%22">Temperature effect</searchLink><br /><searchLink fieldCode="DE" term="%22Electron+distribution%22">Electron distribution</searchLink><br /><searchLink fieldCode="DE" term="%22Phase+transitions%22">Phase transitions</searchLink><br /><searchLink fieldCode="DE" term="%22Thermal+analysis%22">Thermal analysis</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Abstract: We present a model of laser–solid interactions in silicon based on a previously-developed interatomic potential for silicon where the parameters describing the interactions depend on the temperature of the electronic subsystem T e , which is directly related to the density of electron–hole pairs and hence the number of broken covalent bonds. For 25fs pulses, a wide range of fluence values are simulated resulting in heterogeneous melting, homogeneous melting, and ablation. The results presented here demonstrate that phase transitions can usually be described by ordinary thermal processes even when the electronic temperature T e is much greater than the lattice temperature T L during the transition. However, the evolution of the system and details of the phase transitions depend strongly on T e and corresponding density of broken bonds. Homogeneous melting appears to be an ordinary thermal phase transition, but occurring over very fast time scales (1–5ps) before T L reaches the ordinary melting temperature of silicon. For high enough laser fluence, homogeneous melting is followed by rapid expansion of the superheated liquid and ablation. Rapid expansion of the superheated liquid occurs partly due to high pressures generated by a high density of broken bonds. As a result of rapid expansion of the superheated liquid, the system is readily driven into the liquid–vapor coexistence region which initiates phase explosion. These results strongly indicate that phase explosion, generally thought of as an ordinary thermal process, can occur even under strong nonequilibrium conditions when T e ≫ T L . Thus, the results both for melting and ablation processes suggest that for many cases there is no clear separation between thermal and nonthermal processes. Instead, ordinary thermal mechanisms are found to apply when T e ≫ T L , with the high density of broken bonds playing an important role in the detailed evolution of the system. [Copyright &y& Elsevier] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Computational Materials Science is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1016/j.commatsci.2012.07.042 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 13 StartPage: 316 Subjects: – SubjectFull: Silicon Type: general – SubjectFull: Laser ablation Type: general – SubjectFull: Electronic excitation Type: general – SubjectFull: Temperature effect Type: general – SubjectFull: Electron distribution Type: general – SubjectFull: Phase transitions Type: general – SubjectFull: Thermal analysis Type: general Titles: – TitleFull: Role of electronic-excitation effects in the melting and ablation of laser-excited silicon Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Shokeen, Lalit – PersonEntity: Name: NameFull: Schelling, Patrick K. IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 02 Text: Feb2013 Type: published Y: 2013 Identifiers: – Type: issn-print Value: 09270256 Numbering: – Type: volume Value: 67 Titles: – TitleFull: Computational Materials Science Type: main |
| ResultId | 1 |
