Photoluminescence study of Schott commercial and experimental CdSSe-doped glasses: observation of surface states

Hache, F.; Klein, M. C.; Ricard, D.; Flytzanis, C.

doi:10.1364/josab.8.001802

Cited by 75 publications

(20 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…1 from the experimental value at high temperatures (> 200 K) can be explained by this mechanism. The localized excitonic states associated with the surface or defects were found more than several tens of meV below the lowest excitonic state [22]. Thus the transitions to those states occur through multiphonon emission and contribute an almost temperature-independent term to the excitonic dephasing rate giving rise to a constant background which persists even at r=0 K. The almost constant ( -3 meV) deviation of the theoretical pure dephasing rate from the experimental value in Fig.…”

Section: J(t H )Y H Mh (Tl H )\Mt E T H )) L E* M E Ihwhmentioning

confidence: 75%

Electron-phonon interactions and excitonic dephasing in semiconductor nanocrystals

1993

View full text Add to dashboard Cite

The size dependence of the contribution to the excitonic dephasing rate in semiconductor nanocrystals is clarified for various electron-phonon coupling mechanisms. On the basis of these dependencies, the commonly observed linearly temperature-dependent term of the excitonic dephasing rate and the proportionality of its magnitude to the inverse square of the nanocrystal size are attributed to pure dephasing due to deformation-potential coupling. The calculated coefficients of the linearly temperature-dependent term are quantitatively in good agreement with the experimental results on CdSe and CuCl nanocrystals.PACS numbers: 78.66. Li, 71.35.+Z, 73.20.Dx Semiconductor nanocrystals of a size comparable to or smaller than the exciton Bohr radius in bulk material are attracting much attention from the fundamental physics viewpoint and from the interest in the application to functional devices. Especially their novel optical properties due to the discrete electronic energy levels have been investigated extensively [1,2]. In semiconductor nanocrystals, not only the electronic energy levels but also the lattice vibrational modes become discrete due to the threedimensional confinement. The consequences of the latter feature, namely, the phonon confinement, are now being studied extensively. The longitudinal optical (LO) phonons in semiconductor nanocrystals were observed by the resonance Raman scattering [3-5] and the size dependence of the electron-LO-phonon coupling strength was discussed [4]. Also the size-quantized acoustic phonon modes were observed by the low-frequency Raman scattering [6].Recently, in addition to these studies, the excitonic dephasing in various semiconductor nanocrystals has been measured as a function of nanocrystal size and temperature. In CuCl nanocrystals, the homogeneous linewidth of the excitonic transition was measured from the luminescence linewidth under size-selective excitation [7] and by spectral hole burning [8]. In nanocrystals of II-VI compounds, the excitonic dephasing constant was measured by spectral hole burning [9-12] and by fourwave mixing [13,14]. The commonly observed T-(temperature-) linear behavior of the excitonic dephasing rate suggests the importance of the electron-phonon interaction with acoustic phonon modes, although the relevant temperature range is dependent on the nanocrystal size and the material. In the higher temperature region, the temperature dependence of the excitonic dephasing rate deviates from the 7Minear behavior, indicating the participation of LO phonons.In this Letter, we derive electron-phonon interactions with acoustic phonons in semiconductor nanocrystals and clarify the size dependence of the contribution to the excitonic dephasing rate for various electron-phonon coupling mechanisms, i.e., the deformation-potential coupling and the piezoelectric coupling. On the basis of these results, we identify the origin of the commonly observed T-linear term of the excitonic dephasing rate and of the proportionality of its magnitude to the inverse squar...

show abstract

Section: J(t H )Y H Mh (Tl H )\Mt E T H )) L E* M E Ihwhmentioning

confidence: 75%

Electron-phonon interactions and excitonic dephasing in semiconductor nanocrystals

1993

View full text Add to dashboard Cite

show abstract

“…It is suggested that the low-energy band (deep-trap PL) originates from donor-acceptor recombination involving deep defect states, which have been tentatively assigned to surface sulfur vacancies [20]. The high-energy band (band-edge PL) is red-shifted with respect to the 1s(e)-1S 3/2 (h) transition that has been attributed to either a strong coupling of electronic excitations to lattice vibrations [21] or a recombination via localized states, most likely of surface origin [18,22]. The time-resolved measurements shown below clearly indicate a second mechanism for the band-edge emission.…”

Section: Ultrafast Carrier Trapping In Cds Nanocrystalsmentioning

confidence: 99%

Optical nonlinearities and carrier trapping dynamics in CdS and CuxS nanocrystals

Klimov

Bolívar

Kurz

et al. 1996

Superlattices and Microstructures

View full text Add to dashboard Cite

“…Systematic studies by different groups on nanocrystallites have indicated the presence of luminescence due to excitonic emissions as well as significant contribution from surface states on the lower energy side of the photoluminescence ͑PL͒ spectrum. 11 It has also been observed that there is difference in the spectra of ZnO of same size prepared by different methods. The effect of method of preparation and surface passivation itself is an indication that the green emission is due to surface states.…”

Section: Introductionmentioning

confidence: 99%

Size dependent fluorescence spectroscopy of nanocolloids of ZnO

Irimpan

Nampoori

Radhakrishnan

et al. 2007

Journal of Applied Physics

179

View full text Add to dashboard Cite

Intra-excitonic relaxation dynamics in ZnO Appl. Phys. Lett. 99, 231910 (2011) Thermal diffusion of nitrogen into ZnO film deposited on InN/sapphire substrate by metal organic chemical vapor deposition J. Appl. Phys. 110, 113509 (2011) Manifestation of spin-spin interaction between oxygen vacancy and magnesium in ZnMgO nanorods by electron paramagnetic resonance studies Appl. Phys. Lett. 99, 194101 (2011) Selective pair luminescence in the 1.4-eV band of CdTe:In J. Appl. Phys. 110, 093103 (2011) Evidence of cation vacancy induced room temperature ferromagnetism in Li-N codoped ZnO thin films Appl. Phys. Lett. 99, 182503 (2011) Additional information on J. Appl. Phys. In this article we present size dependent spectroscopic observations of nanocolloids of ZnO. ZnO is reported to show two emission bands, an ultraviolet ͑UV͒ emission band and another in the green region. Apart from the known band gap 380 nm and impurity 530 nm emissions, we have found some peculiar features in the fluorescence spectra that are consistent with the nanoparticle size distribution. Results show that additional emissions at 420 and 490 nm are developed with particle size. The origin of the visible band emission is discussed. The mechanism of the luminescence suggests that UV luminescence of ZnO colloid is related to the transition from conduction band edge to valence band, and visible luminescence is caused by the transition from deep donor level to valence band due to oxygen vacancies and by the transition from conduction band to deep acceptor level due to impurities and defect states. A correlation analysis between the particle size and spectroscopic observations is also discussed.

show abstract

Photoluminescence study of Schott commercial and experimental CdSSe-doped glasses: observation of surface states

Cited by 75 publications

References 30 publications

Electron-phonon interactions and excitonic dephasing in semiconductor nanocrystals

Electron-phonon interactions and excitonic dephasing in semiconductor nanocrystals

Optical nonlinearities and carrier trapping dynamics in CdS and CuxS nanocrystals

Size dependent fluorescence spectroscopy of nanocolloids of ZnO

Contact Info

Product

Resources

About