Surface optical phonons in GaAs nanowires grown by Ga-assisted chemical beam epitaxy

Carlos García Núñez; A.F. Braña; Jose L. Pau; Daniel Ghita; Basilio J. Garcia; G. Shen; D.S. Wilbert; S.M. Kim; Patrick Kung

doi:10.1063/1.4862742

Surface optical phonons in GaAs nanowires grown by Ga-assisted chemical beam epitaxy

Carlos García Núñez, A.F. Braña, Jose L. Pau, Daniel Ghita, Basilio J. Garcia, G. Shen, D.S. Wilbert, S.M. Kim, Patrick Kung

Research output: Contribution to journal › Article › peer-review

Abstract

Surface optical (SO) phonons were studied by Raman spectroscopy in GaAs nanowires (NWs) grown by Ga-assisted chemical beam epitaxy on oxidized Si(111) substrates. NW diameters and lengths ranging between 40 and 65 nm and between 0.3 and 1.3 μm, respectively, were observed under different growth conditions. The analysis of the Raman peak shape associated to either longitudinal or surface optical modes gave important information about the crystal quality of grown NWs. Phonon confinement model was used to calculate the density of defects as a function of the NW diameter resulting in values between 0.02 and 0.03 defects/nm, indicating the high uniformity obtained on NWs cross section size during growth. SO mode shows frequency downshifting as NW diameter decreases, this shift being sensitive to NW sidewall oxidation. The wavevector necessary to activate SO phonon was used to estimate the NW facet roughness responsible for SO shift.

Original language	English
Article number	034307
Journal	Journal of Applied Physics
Volume	115
Issue number	3
DOIs	https://doi.org/10.1063/1.4862742
Publication status	Published - 21 Jan 2014
Externally published	Yes

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@article{4d54adaab37e4679866dc74afc210f8f,

title = "Surface optical phonons in GaAs nanowires grown by Ga-assisted chemical beam epitaxy",

abstract = "Surface optical (SO) phonons were studied by Raman spectroscopy in GaAs nanowires (NWs) grown by Ga-assisted chemical beam epitaxy on oxidized Si(111) substrates. NW diameters and lengths ranging between 40 and 65 nm and between 0.3 and 1.3 μm, respectively, were observed under different growth conditions. The analysis of the Raman peak shape associated to either longitudinal or surface optical modes gave important information about the crystal quality of grown NWs. Phonon confinement model was used to calculate the density of defects as a function of the NW diameter resulting in values between 0.02 and 0.03 defects/nm, indicating the high uniformity obtained on NWs cross section size during growth. SO mode shows frequency downshifting as NW diameter decreases, this shift being sensitive to NW sidewall oxidation. The wavevector necessary to activate SO phonon was used to estimate the NW facet roughness responsible for SO shift.",

author = "{Garc{\'i}a N{\'u}{\~n}ez}, Carlos and A.F. Bra{\~n}a and Pau, {Jose L.} and Daniel Ghita and Garcia, {Basilio J.} and G. Shen and D.S. Wilbert and S.M. Kim and Patrick Kung",

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year = "2014",

month = jan,

day = "21",

doi = "10.1063/1.4862742",

language = "English",

volume = "115",

journal = "Journal of Applied Physics",

issn = "0021-8979",

publisher = "American Institute of Physics",

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TY - JOUR

T1 - Surface optical phonons in GaAs nanowires grown by Ga-assisted chemical beam epitaxy

AU - García Núñez, Carlos

AU - Braña, A.F.

AU - Pau, Jose L.

AU - Ghita, Daniel

AU - Garcia, Basilio J.

AU - Shen, G.

AU - Wilbert, D.S.

AU - Kim, S.M.

AU - Kung, Patrick

N1 - ORCID Reference type: [bibtex]; ORCID Reference: [@article{RID:0802150713882-2, title = {Surface optical phonons in GaAs nanowires grown by Ga-assisted chemical beam epitaxy}, journal = {Journal of Applied Physics}, year = {2014}, author = {Garcia Nunez, C. and Brana, A. F. and Pau, J. L. and Ghita, D. and Garcia, B. J. and Shen, G. and Wilbert, D. S. and Kim, S. M. and Kung, P.}, volume = {115}, number = {3} }]

PY - 2014/1/21

Y1 - 2014/1/21

N2 - Surface optical (SO) phonons were studied by Raman spectroscopy in GaAs nanowires (NWs) grown by Ga-assisted chemical beam epitaxy on oxidized Si(111) substrates. NW diameters and lengths ranging between 40 and 65 nm and between 0.3 and 1.3 μm, respectively, were observed under different growth conditions. The analysis of the Raman peak shape associated to either longitudinal or surface optical modes gave important information about the crystal quality of grown NWs. Phonon confinement model was used to calculate the density of defects as a function of the NW diameter resulting in values between 0.02 and 0.03 defects/nm, indicating the high uniformity obtained on NWs cross section size during growth. SO mode shows frequency downshifting as NW diameter decreases, this shift being sensitive to NW sidewall oxidation. The wavevector necessary to activate SO phonon was used to estimate the NW facet roughness responsible for SO shift.

AB - Surface optical (SO) phonons were studied by Raman spectroscopy in GaAs nanowires (NWs) grown by Ga-assisted chemical beam epitaxy on oxidized Si(111) substrates. NW diameters and lengths ranging between 40 and 65 nm and between 0.3 and 1.3 μm, respectively, were observed under different growth conditions. The analysis of the Raman peak shape associated to either longitudinal or surface optical modes gave important information about the crystal quality of grown NWs. Phonon confinement model was used to calculate the density of defects as a function of the NW diameter resulting in values between 0.02 and 0.03 defects/nm, indicating the high uniformity obtained on NWs cross section size during growth. SO mode shows frequency downshifting as NW diameter decreases, this shift being sensitive to NW sidewall oxidation. The wavevector necessary to activate SO phonon was used to estimate the NW facet roughness responsible for SO shift.

U2 - 10.1063/1.4862742

DO - 10.1063/1.4862742

M3 - Article

SN - 0021-8979

VL - 115

JO - Journal of Applied Physics

JF - Journal of Applied Physics

IS - 3

M1 - 034307

ER -

Surface optical phonons in GaAs nanowires grown by Ga-assisted chemical beam epitaxy

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