Spectroscopy and carrier dynamics in CdSe self-assembled quantum dots embedded in ZnxCdyMg1−x−ySe

Comanescu, G.; Wang, W. B.; Gundry, Stephen; Das, B. B.; Alfano, R. R.; Perez-Paz, M. Noemi; Tamargo, M. C.; Muñoz, Martı́n; Попов, И. И.; Isaacs, L. L.

doi:10.1063/1.1947909

Cited by 5 publications

(4 citation statements)

References 13 publications

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“…The rise time is determined by fitting the rising process with the Boltzmann sigmoidal function where B 1 is the initial value, B 2 is the final value, t s indicates the time center, and τ R represents the time constant for the rising process. The rise time (τ R ) for FX obtained from the fitting is 101 ± 5 ps (results shown in Figure a), which value is larger than that in CdSe QDs (20–40 ps). , The decay curve of the QD samples can be well-fitted by a double-exponential function where I b represents the noise. The fitting results are plotted as solid lines in Figure a.…”

Section: Results and Discussionmentioning

confidence: 87%

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Ultrafast Charge Carrier Dynamics and Nonlinear Optical Absorption of InP/ZnS Core–Shell Colloidal Quantum Dots

Zhang

Wang

et al. 2019

J. Phys. Chem. C

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Understanding of ultrafast carrier dynamics in InP/ZnS colloidal quantum dots (QDs) is essential for their optoelectronic applications. In this paper, we have successfully fabricated high-quality InP/ZnS core–shell QDs with quantum yield (QY) of 47%. Time-resolved photoluminescence (TRPL) and femtosecond transient absorption (TAS) measurements were performed to characterize the carrier injection, relaxation, and transition process in the InP/ZnS QDs. It is found that the photoexcited carrier first injected to the ZnS shell in 2 ps, then relaxed to the alloyed layer between the ZnS shell and InP core in 7.4 ps, next relaxed to different energy levels in the InP core in about 170 ps, and finally recombined by charged and neutral excitons transition in 4.1 and 26.7 ns, respectively. Additionally, the two-photon absorption (TPA) coefficient obtained from Z-scan measurement indicates that InP/ZnS QDs possess good nonlinearly optical properties. Our research is significant for the improvement and engineering of InP/ZnS QDs-based materials for optoelectronic applications.

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Section: Results and Discussionmentioning

confidence: 87%

“…The rise time (τ R ) for FX obtained from the fitting is 101 ± 5 ps (results shown in Figure 4a), 39 which value is larger than that in CdSe QDs (20−40 ps). 40,41 The decay curve of the QD samples can be well-fitted by a double-exponential function 38…”

Section: E E Ementioning

confidence: 99%

Ultrafast Charge Carrier Dynamics and Nonlinear Optical Absorption of InP/ZnS Core–Shell Colloidal Quantum Dots

Zhang

Wang

et al. 2019

J. Phys. Chem. C

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“…The CdSe SAQDs have very high ionization energy due to the larger size; and its crystal lattice is coherently connected to the host ZnSe matrix (high quality dislocation-free interface). The results of carrier dynamics in CdSe SAQDs from [17] suggest that the recombination processes are inherently faster in smaller QDs. In fact, we observed that the high-energy part of the NCs PL peak has a faster relaxation than the low-energy part (the smaller the NC size, the higher the energy of the PL emission), as is clearly shown in figure 6(a).…”

Section: Optical Characterizationsmentioning

confidence: 99%

Improving carrier injection in colloidal CdSe nanocrystals by embedding them in a pseudomorphic ZnSe/ZnMgSe quantum well structure

et al. 2013

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The incorporation of colloidal nanocrystals in a high crystalline quality semiconductor matrix, the efficient carrier injection into the embedded nanocrystals and the fast optical response are key features for the fabrication of novel optoelectronic nanodevices based on colloidal nanostructures as active optical material. Using a novel growth approach, colloidal bare CdSe and core-shell CdSe/ZnS nanocrystals were monolithically incorporated in pseudomorphic ZnSe/ZnMgSe quantum wells in order to control and enhance the carrier transfer into the nanocrystals. The photoluminescence for bare CdSe nanocrystals incorporated in ZnSe/ZnMgSe quantum well structures is substantially enhanced in comparison to nanocrystals sandwiched in ZnSe epilayers, which we attribute to increased carrier injection into the embedded nanocrystals via the quantum well, resembling the function of a wetting layer in Stranski-Krastanov-grown quantum dots. Core-shell CdSe/ZnS nanocrystals embedded in quantum well structures do not show considerable PL modifications because the ZnS shell prevents the efficient carrier migration between the nanocrystal and the matrix. Systematic investigations of structural and optical properties by high-resolution x-ray diffraction, temperature-dependent photoluminescence and time-resolved emission are presented.

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“…The experiment was carried out with a cw-He-Cd laser at a 325 nm excitation wavelength and at 2 mW power. The typical spectra of the photoluminescence of CdSe/ZnCdMgSe QDs are presented in [2,8]. The emission peak of the PL was centred at 585 nm at room temperature, and its full width at half-maximum (FWHM) was about 8 nm for the sample used.…”

Section: Cw Low Power Excitationmentioning

confidence: 99%

High resolution ultraviolet-to-visible image conversion using self-assembled CdSe/ZnCdMgSe quantum dot photoluminescence

Zeylikovich

Tamargo

Alfano

2007

J. Phys. B: At. Mol. Opt. Phys.

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High resolution ultraviolet-to-visible image conversion using photoluminescence emitted by self-assembled CdSe/ZnCdMgSe quantum dots was investigated. The visible images centred at 585 nm with a resolution of 2 µm and 5 µm were obtained using a cw-He-Cd laser at the 325 nm excitation wavelength and with 150 fs laser pulses tuned to the second harmonic generation at 400 nm, respectively. The resolution limitations of visible images are discussed, and a high resolution optical system for the ultraviolet-to-visible image conversion is proposed.

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Spectroscopy and carrier dynamics in CdSe self-assembled quantum dots embedded in ZnxCdyMg1−x−ySe

Abstract: Articles you may be interested inEffect of metal oxide morphology on electron injection from CdSe quantum dots to ZnO

Cited by 5 publications

References 13 publications

Ultrafast Charge Carrier Dynamics and Nonlinear Optical Absorption of InP/ZnS Core–Shell Colloidal Quantum Dots

Ultrafast Charge Carrier Dynamics and Nonlinear Optical Absorption of InP/ZnS Core–Shell Colloidal Quantum Dots

Improving carrier injection in colloidal CdSe nanocrystals by embedding them in a pseudomorphic ZnSe/ZnMgSe quantum well structure

High resolution ultraviolet-to-visible image conversion using self-assembled CdSe/ZnCdMgSe quantum dot photoluminescence

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