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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Raman scattering in cluster-deposited nanogranular silicon films
AU - Konstantinovic, Milan J
AU - Bersier, Stefan
AU - Wang, Xin
AU - Hayne, M
AU - Lievens, Peter
AU - Silverans, Roger E
AU - Moshchalkov, Victor V
N1 - © 2002 The American Physical Society
PY - 2002/10/15
Y1 - 2002/10/15
N2 - We study nanograin size confinement effects, and the effect of the increase of local temperature on the first-order Raman spectrum in silicon nanogranular films obtained by cluster deposition. The local temperature was monitored by measuring the Stokes/antiStokes peak ratio with the laser power up to similar to20 kW/cm(2). We find large energy shifts, up to 30 cm(-1), and broadenings, up to 20 cm(-1), of the Raman-active mode, which we attribute to both laser heating and confinement effects. The phonon softening and phonon linewidth are calculated using a phenomenological model which takes into account disorder effects through the breakdown of the k = 0 Raman-scattering selection rule, and also anharmonicity, which is incorporated through the three- and four- phonon decay processes. Very good agreement with experimental data is obtained for calculated spectra with nanograin sizes of about 10 nm, and with an increase in the anisotropy constants with respect to those of bulk silicon.
AB - We study nanograin size confinement effects, and the effect of the increase of local temperature on the first-order Raman spectrum in silicon nanogranular films obtained by cluster deposition. The local temperature was monitored by measuring the Stokes/antiStokes peak ratio with the laser power up to similar to20 kW/cm(2). We find large energy shifts, up to 30 cm(-1), and broadenings, up to 20 cm(-1), of the Raman-active mode, which we attribute to both laser heating and confinement effects. The phonon softening and phonon linewidth are calculated using a phenomenological model which takes into account disorder effects through the breakdown of the k = 0 Raman-scattering selection rule, and also anharmonicity, which is incorporated through the three- and four- phonon decay processes. Very good agreement with experimental data is obtained for calculated spectra with nanograin sizes of about 10 nm, and with an increase in the anisotropy constants with respect to those of bulk silicon.
KW - POROUS SILICON
KW - DEPENDENCE
KW - PHONONS
KW - DENSITY
KW - SPECTRA
KW - STATES
KW - GAAS
KW - SI
U2 - 10.1103/PhysRevB.66.161311
DO - 10.1103/PhysRevB.66.161311
M3 - Journal article
VL - 66
SP - -
JO - Physical review B
JF - Physical review B
SN - 1550-235X
IS - 16
M1 - 161311
ER -