Raman scattering and phonon dispersion in Si and GaP at very high pressure

Weinstein, B. A.; Piermarini, G. J.

doi:10.1103/physrevb.12.1172

Cited by 479 publications

(172 citation statements)

References 58 publications

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“…11(b)) observed positions of the Si-Si(Ge) Raman peak is $15 cm À1 , and it can be associated with a considerable laser heating induced thermal stress of the order of 2-3 GPa. 49,50 Stress is known to affect the Raman polarization dependence in Si/SiGe nanostructures, 51 and this notion explains the experimental data shown in Fig. 8.…”

Section: Discussionsupporting

confidence: 67%

Structural and optical properties of axial silicon-germanium nanowire heterojunctions

Wang

Tsybeskov

Kamins

et al. 2015

Journal of Applied Physics

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Access and use of this website and the material on it are subject to the Terms and Conditions set forth at NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE.http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca.

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Section: Discussionsupporting

confidence: 67%

Structural and optical properties of axial silicon-germanium nanowire heterojunctions

Wang

Tsybeskov

Kamins

et al. 2015

Journal of Applied Physics

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“…Using a bulk value [26] for χ T = 0.01012 GPa −1 , the mode Grüneisen parameter is calculated to be 1.12, which is in agreement with other findings [27,28].…”

supporting

confidence: 77%

Recovery of hexagonal Si-IV nanowires from extreme GPa pressure

Smith

Zhou

Roder

et al. 2016

Journal of Applied Physics

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We use Raman spectroscopy in tandem with transmission electron microscopy and DFT simulations to show that extreme (GPa) pressure converts the phase of silicon nanowires from cubic (Si-I) to hexagonal (Si-IV) while preserving the nanowire's cylindrical morphology. In situ Raman scattering of the TO mode demonstrates the high-pressure Si-I to Si-II phase transition near 9 GPa. Raman signal of the TO phonon shows a decrease in intensity in the range 9 to 14 GPa. Then, at 17 GPa, it is no longer detectable, indicating a second phase change (Si-II to Si-V) in the 14 to 17 GPa range. Recovery of exotic phases in individual silicon nanowires from diamond anvil cell experiments reaching 17 GPa is also shown. Raman measurements indicate Si-IV as the dominant phase in pressurized nanowires after decompression. Transmission electron microscopy and electron diffraction confirm crystalline Si-IV domains in individual nanowires. Computational electromagnetic simulations suggest that heating from the Raman laser probe is negligible and that near-hydrostatic pressure is the primary driving force for the formation of hexagonal silicon nanowires.Silicon is the second most abundant element in the Earth's crust [1] and the foundation of the modern electronics industry. It is used for integrated circuits in information technology and as an energy conversion material in photovoltaics. Unfortunately, one of the biggest drawbacks for silicon's use in solar energy conversion is its indirect band gap. Theoretical [2,3] and experimental [4][5][6] efforts are looking at the properties of exotic phases of silicon and their potential as improved photovoltaic (PV) absorbers.The phase diagram of silicon [7] reveals several polytypes at elevated pressures. At a pressure of ∼11 GPa, Si-I begins to transition to Si-II which has a body-centered tetragonal crystal structure and metallic electronic structure [8]. As pressure increases past approximately 15 GPa, Si-V begins to emerge with a primitive hexagonal phase [9][10][11]. But neither Si-II nor Si-V are stable at atmospheric pressure and, therefore, have not been observed experimentally outside of high pressures. Si-III (body-centered cubic) and Si-IV (diamond hexagonal), however, are stable at atmospheric pressure and have been synthetisized [4,12,13] as well as recovered from high-pressure phase transitions [14,15]. While Si-III is a semimetal [14] and could have applications in electronics, Si-IV is a semiconductor with a reported indirect band gap near 0.8-0.9 eV and direct transition at 1.5 eV [13]. The direct transition for Si-IV makes * peterpz@uw.edu FIG. 1. Schematic of the diamond anvil cell (DAC) and components for Raman scattering measurements. A holographic laser bandpass (HLB) filter is used to pass the 532 nm Raman probe into a 50x objective which focused the beam into DAC. Nanowire Raman scattering and ruby photoluminescence were collected with the same objective and sent to a spectrometer or CCD for imaging. A 532 nm notch filter (NF) was used to eliminate strong Rayleigh scat...

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“…13,14 Raman scattering, or more generally inelastic light scattering is a standard nondestructive contactless characterization technique of materials, which allows to access mainly the phonon modes at the ⌫ point and in some cases to the dispersion. [15][16][17] Raman spectroscopy can be realized by using a confocal microscope, thereby obtaining lateral submicron resolutions of the properties of a material. It has been developed to be a versatile tool for the characterization of semiconductors leading to detailed information on crystal structure, phonon dispersion, electronic states, composition, strain and so on of semiconductor nanostructures or nanowires.…”

Section: Introductionmentioning

confidence: 99%

Raman spectroscopy of wurtzite and zinc-blende GaAs nanowires: Polarization dependence, selection rules, and strain effects

et al. 2009

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Polarization-dependent Raman scattering experiments realized on single GaAs nanowires with different percentages of zinc-blende and wurtzite structure are presented. The selection rules for the special case of nanowires are found and discussed. In the case of zinc-blende, the transversal optical mode E 1 ͑TO͒ at 267 cm −1 exhibits the highest intensity when the incident and analyzed polarization are parallel to the nanowire axis. This is a consequence of the nanowire geometry and dielectric mismatch with the environment, and in quite good agreement with the Raman selection rules. We also find a consistent splitting of 1 cm −1 of the E 1 ͑TO͒. The transversal optical mode related to the wurtzite structure, E 2 H , is measured between 254 and 256 cm −1 , depending on the wurtzite content. The azimuthal dependence of E 2 H indicates that the mode is excited with the highest efficiency when the incident and analyzed polarization are perpendicular to the nanowire axis, in agreement with the selection rules. The presence of strain between wurtzite and zinc-blende is analyzed by the relative shift of the E 1 ͑TO͒ and E 2 H modes. Finally, the influence of the surface roughness in the intensity of the longitudinal optical mode on ͕110͖ facets is presented.

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Raman scattering and phonon dispersion in Si and GaP at very high pressure

Cited by 479 publications

References 58 publications

Structural and optical properties of axial silicon-germanium nanowire heterojunctions

Structural and optical properties of axial silicon-germanium nanowire heterojunctions

Recovery of hexagonal Si-IV nanowires from extreme GPa pressure

Raman spectroscopy of wurtzite and zinc-blende GaAs nanowires: Polarization dependence, selection rules, and strain effects

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