Abstract
We have studied the relaxation mechanism of localized excitons at optically active defect centers in cuprous oxide by the photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopies. We find that the temperature dependence of the PL and PLE spectra of the oxygen vacancy emission is well explained by the adiabatic potential model. The Huang-Rhys factors for the absorption and emission processes are obtained as ∼8, indicating the medium coupling of the exciton-phonon interaction. The effective frequencies of the vibrational levels are obtained as 16.5 meV and 16.1 meV, respectively, for the excited and ground states. These results indicate the Stokes shift of 0.269 ±0.008 eV which is released from the localized excitons as the lattice relaxation energy by phonon emission. Our energy level diagram resolves the previous discrepancy between the small activation energy and the large separation of the luminescence photon energies for free and localized excitons.
| Original language | English |
|---|---|
| Pages (from-to) | 65-69 |
| Number of pages | 5 |
| Journal | Journal of Luminescence |
| Volume | 155 |
| DOIs | |
| Publication status | Published - 2014 Jan 1 |
| Externally published | Yes |
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Keywords
- Adiabatic potential model
- Defect center
- Relaxed exciton
ASJC Scopus subject areas
- Biophysics
- Chemistry(all)
- Atomic and Molecular Physics, and Optics
- Biochemistry
- Condensed Matter Physics
Cite this
Relaxation of localized excitons by phonon emission at oxygen vacancies in Cu2O. / Koirala, Sandhaya; Takahata, Mitsuyoshi; Hazama, Yuji; Naka, Nobuko; Tanaka, Koichiro.
In: Journal of Luminescence, Vol. 155, 01.01.2014, p. 65-69.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Relaxation of localized excitons by phonon emission at oxygen vacancies in Cu2O
AU - Koirala, Sandhaya
AU - Takahata, Mitsuyoshi
AU - Hazama, Yuji
AU - Naka, Nobuko
AU - Tanaka, Koichiro
PY - 2014/1/1
Y1 - 2014/1/1
N2 - We have studied the relaxation mechanism of localized excitons at optically active defect centers in cuprous oxide by the photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopies. We find that the temperature dependence of the PL and PLE spectra of the oxygen vacancy emission is well explained by the adiabatic potential model. The Huang-Rhys factors for the absorption and emission processes are obtained as ∼8, indicating the medium coupling of the exciton-phonon interaction. The effective frequencies of the vibrational levels are obtained as 16.5 meV and 16.1 meV, respectively, for the excited and ground states. These results indicate the Stokes shift of 0.269 ±0.008 eV which is released from the localized excitons as the lattice relaxation energy by phonon emission. Our energy level diagram resolves the previous discrepancy between the small activation energy and the large separation of the luminescence photon energies for free and localized excitons.
AB - We have studied the relaxation mechanism of localized excitons at optically active defect centers in cuprous oxide by the photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopies. We find that the temperature dependence of the PL and PLE spectra of the oxygen vacancy emission is well explained by the adiabatic potential model. The Huang-Rhys factors for the absorption and emission processes are obtained as ∼8, indicating the medium coupling of the exciton-phonon interaction. The effective frequencies of the vibrational levels are obtained as 16.5 meV and 16.1 meV, respectively, for the excited and ground states. These results indicate the Stokes shift of 0.269 ±0.008 eV which is released from the localized excitons as the lattice relaxation energy by phonon emission. Our energy level diagram resolves the previous discrepancy between the small activation energy and the large separation of the luminescence photon energies for free and localized excitons.
KW - Adiabatic potential model
KW - Defect center
KW - Relaxed exciton
UR - http://www.scopus.com/inward/record.url?scp=84903954110&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84903954110&partnerID=8YFLogxK
U2 - 10.1016/j.jlumin.2014.06.027
DO - 10.1016/j.jlumin.2014.06.027
M3 - Article
VL - 155
SP - 65
EP - 69
JO - Journal of Luminescence
JF - Journal of Luminescence
SN - 0022-2313
ER -