Abstract
We performed spin-polarized resonant Raman and resonant photoluminescence excitation spectroscopy (also known as "fluorescence line narrowing") on ZnS-capped CdSe nanocrystal quantum dots in high magnetic fields to 33 Tesla and temperatures down to 1.7K, which allows detailed investigation of the excitonic spin states. In these experiments, spin-polarized electrons and holes are resonantly injected by circularly polarized light into colloidal quantum dots of specific size, using a narrowband tunable dye laser and a fiber-coupled probe that is specially-designed for use in high-field magnets. In addition to the expected broad features associated with excitonic recombination and Raman-like peaks associated with quantized acoustic phonons, the photoluminescence spectra measured at magnetic fields larger than 10 Tesla develop a sharp peak, which moves roughly linearly with applied magnetic field. Further, the energy of this high-field peak varies systematically as a function of nanocrystal size. However, unlike typical electron spin flip transitions, the mode energy extrapolates to a finite value at zero magnetic field, suggesting the existence of an additional size-dependent exchange mechanism.
| Original language | English |
|---|---|
| Pages (from-to) | 3769-3774 |
| Number of pages | 6 |
| Journal | International Journal of Modern Physics B |
| Volume | 18 |
| Issue number | 27-29 |
| DOIs | |
| Publication status | Published - Nov 30 2004 |
Fingerprint
Keywords
- CdSe nanocrystals
- Line-narrowing
- Photoluminescence
- Zeeman splitting
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)
- Condensed Matter Physics
- Electronic, Optical and Magnetic Materials
- Statistical and Nonlinear Physics
- Mathematical Physics
Cite this
Exciton spin states in nanocrystal quantum dots revealed by spin-polarized resonant photoluminescence and raman spectroscopy. / Furis, Madalina; Barrick, Todd; Robbins, Patrick; Crooker, Scott A.; Petruska, Melissa; Klimov, Victor I; Efros, Al L.
In: International Journal of Modern Physics B, Vol. 18, No. 27-29, 30.11.2004, p. 3769-3774.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Exciton spin states in nanocrystal quantum dots revealed by spin-polarized resonant photoluminescence and raman spectroscopy
AU - Furis, Madalina
AU - Barrick, Todd
AU - Robbins, Patrick
AU - Crooker, Scott A.
AU - Petruska, Melissa
AU - Klimov, Victor I
AU - Efros, Al L.
PY - 2004/11/30
Y1 - 2004/11/30
N2 - We performed spin-polarized resonant Raman and resonant photoluminescence excitation spectroscopy (also known as "fluorescence line narrowing") on ZnS-capped CdSe nanocrystal quantum dots in high magnetic fields to 33 Tesla and temperatures down to 1.7K, which allows detailed investigation of the excitonic spin states. In these experiments, spin-polarized electrons and holes are resonantly injected by circularly polarized light into colloidal quantum dots of specific size, using a narrowband tunable dye laser and a fiber-coupled probe that is specially-designed for use in high-field magnets. In addition to the expected broad features associated with excitonic recombination and Raman-like peaks associated with quantized acoustic phonons, the photoluminescence spectra measured at magnetic fields larger than 10 Tesla develop a sharp peak, which moves roughly linearly with applied magnetic field. Further, the energy of this high-field peak varies systematically as a function of nanocrystal size. However, unlike typical electron spin flip transitions, the mode energy extrapolates to a finite value at zero magnetic field, suggesting the existence of an additional size-dependent exchange mechanism.
AB - We performed spin-polarized resonant Raman and resonant photoluminescence excitation spectroscopy (also known as "fluorescence line narrowing") on ZnS-capped CdSe nanocrystal quantum dots in high magnetic fields to 33 Tesla and temperatures down to 1.7K, which allows detailed investigation of the excitonic spin states. In these experiments, spin-polarized electrons and holes are resonantly injected by circularly polarized light into colloidal quantum dots of specific size, using a narrowband tunable dye laser and a fiber-coupled probe that is specially-designed for use in high-field magnets. In addition to the expected broad features associated with excitonic recombination and Raman-like peaks associated with quantized acoustic phonons, the photoluminescence spectra measured at magnetic fields larger than 10 Tesla develop a sharp peak, which moves roughly linearly with applied magnetic field. Further, the energy of this high-field peak varies systematically as a function of nanocrystal size. However, unlike typical electron spin flip transitions, the mode energy extrapolates to a finite value at zero magnetic field, suggesting the existence of an additional size-dependent exchange mechanism.
KW - CdSe nanocrystals
KW - Line-narrowing
KW - Photoluminescence
KW - Zeeman splitting
UR - http://www.scopus.com/inward/record.url?scp=17644404397&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=17644404397&partnerID=8YFLogxK
U2 - 10.1142/S0217979204027438
DO - 10.1142/S0217979204027438
M3 - Article
AN - SCOPUS:17644404397
VL - 18
SP - 3769
EP - 3774
JO - International Journal of Modern Physics B
JF - International Journal of Modern Physics B
SN - 0217-9792
IS - 27-29
ER -