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Title: Second Harmonic Generation and Confined Acoustic Phonons in HighlyExcited Semiconductor Nanocrystals

Abstract

The photo-induced enhancement of second harmonic generation, and the effect of nanocrystal shape and pump intensity on confined acoustic phonons in semiconductor nanocrystals, has been investigated with time-resolved scattering and absorption measurements. The second harmonic signal showed a sublinear increase of the second order susceptibility with respect to the pump pulse energy, indicating a reduction of the effective one-electron second-order nonlinearity with increasing electron-hole density in the nanocrystals. The coherent acoustic phonons in spherical and rod-shaped semiconductor nanocrystals were detected in a time-resolved absorption measurement. Both nanocrystal morphologies exhibited oscillatory modulation of the absorption cross section, the frequency of which corresponded to their coherent radial breathing modes. The amplitude of the oscillation also increased with the level of photoexcitation, suggesting an increase in the amplitude of the lattice displacement as well.

Authors:
; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Director. Office of Science. Office of Basic EnergySciences; Department of Defense. MURI program FA9550-04-1-0242
OSTI Identifier:
901818
Report Number(s):
LBNL-59948
R&D Project: 508401; BnR: KC0203010; TRN: US200715%%155
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry B
Additional Journal Information:
Journal Volume: 110; Journal Issue: 40; Related Information: Journal Publication Date: 2006
Country of Publication:
United States
Language:
English
Subject:
36; ABSORPTION; ACOUSTICS; AMPLITUDES; CROSS SECTIONS; HARMONIC GENERATION; HARMONICS; MODULATION; OSCILLATIONS; PHONONS; RESPIRATION; SCATTERING; SHAPE; Materials Nanocrystal Ultrafast

Citation Formats

Son, Dong Hee, Wittenberg, Joshua S, Banin, Uri, and Alivisatos, A Paul. Second Harmonic Generation and Confined Acoustic Phonons in HighlyExcited Semiconductor Nanocrystals. United States: N. p., 2006. Web. doi:10.1021/jp062028o.
Son, Dong Hee, Wittenberg, Joshua S, Banin, Uri, & Alivisatos, A Paul. Second Harmonic Generation and Confined Acoustic Phonons in HighlyExcited Semiconductor Nanocrystals. United States. https://doi.org/10.1021/jp062028o
Son, Dong Hee, Wittenberg, Joshua S, Banin, Uri, and Alivisatos, A Paul. 2006. "Second Harmonic Generation and Confined Acoustic Phonons in HighlyExcited Semiconductor Nanocrystals". United States. https://doi.org/10.1021/jp062028o. https://www.osti.gov/servlets/purl/901818.
@article{osti_901818,
title = {Second Harmonic Generation and Confined Acoustic Phonons in HighlyExcited Semiconductor Nanocrystals},
author = {Son, Dong Hee and Wittenberg, Joshua S and Banin, Uri and Alivisatos, A Paul},
abstractNote = {The photo-induced enhancement of second harmonic generation, and the effect of nanocrystal shape and pump intensity on confined acoustic phonons in semiconductor nanocrystals, has been investigated with time-resolved scattering and absorption measurements. The second harmonic signal showed a sublinear increase of the second order susceptibility with respect to the pump pulse energy, indicating a reduction of the effective one-electron second-order nonlinearity with increasing electron-hole density in the nanocrystals. The coherent acoustic phonons in spherical and rod-shaped semiconductor nanocrystals were detected in a time-resolved absorption measurement. Both nanocrystal morphologies exhibited oscillatory modulation of the absorption cross section, the frequency of which corresponded to their coherent radial breathing modes. The amplitude of the oscillation also increased with the level of photoexcitation, suggesting an increase in the amplitude of the lattice displacement as well.},
doi = {10.1021/jp062028o},
url = {https://www.osti.gov/biblio/901818}, journal = {Journal of Physical Chemistry B},
number = 40,
volume = 110,
place = {United States},
year = {Thu Mar 30 00:00:00 EST 2006},
month = {Thu Mar 30 00:00:00 EST 2006}
}