Limits...
Strong localization effect and carrier relaxation dynamics in self-assembled InGaN quantum dots emitting in the green.

Weng GE, Zhao WR, Chen SQ, Akiyama H, Li ZC, Liu JP, Zhang BP - Nanoscale Res Lett (2015)

Bottom Line: The integrated emission intensity increases gradually in the range from 30 to 160 K and then decreases with a further increase in temperature at high excitation intensity, while this phenomenon disappeared at low excitation intensity.Under high excitation, about 40% emission enhancement at 160 K compared to that at low temperature, as well as a higher internal quantum efficiency (IQE) of 41.1%, was observed.Using this model, the evolution of excitation-power-dependent emission intensity, shift of peak energy, and linewidth variation with elevating temperature is well explained.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics and Semiconductor Photonics Research Center, Xiamen University, 422 South Siming Road, Xiamen, 361005 P. R. China.

ABSTRACT
Strong localization effect in self-assembled InGaN quantum dots (QDs) grown by metalorganic chemical vapor deposition has been evidenced by temperature-dependent photoluminescence (PL) at different excitation power. The integrated emission intensity increases gradually in the range from 30 to 160 K and then decreases with a further increase in temperature at high excitation intensity, while this phenomenon disappeared at low excitation intensity. Under high excitation, about 40% emission enhancement at 160 K compared to that at low temperature, as well as a higher internal quantum efficiency (IQE) of 41.1%, was observed. A strong localization model is proposed to describe the possible processes of carrier transport, relaxation, and recombination. Using this model, the evolution of excitation-power-dependent emission intensity, shift of peak energy, and linewidth variation with elevating temperature is well explained. Finally, two-component decays of time-resolved PL (TRPL) with various excitation intensities are observed and analyzed with the biexponential model, which enables us to further understand the carrier relaxation dynamics in the InGaN QDs.

No MeSH data available.


Related in: MedlinePlus

TRPL decay curves of the QDs at different excitation power. The solid curves are biexponential fits to experiment data. The inset shows temporal variation of the peak energy of the PL spectra.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4384949&req=5

Fig6: TRPL decay curves of the QDs at different excitation power. The solid curves are biexponential fits to experiment data. The inset shows temporal variation of the peak energy of the PL spectra.

Mentions: In order to further clarify the carrier transfer process and relaxation dynamics of the InGaN QDs, TRPL measurements are performed by fs impulsive excitation at room temperature. As shown in FigureĀ 6, the normalized TRPL decay curves with varied excitation densities exhibit two obvious decay stages, which are relatively faster in the early stage and slower in the extended range. The decay curves can be well fitted with a biexponential function [26]:Figure 6


Strong localization effect and carrier relaxation dynamics in self-assembled InGaN quantum dots emitting in the green.

Weng GE, Zhao WR, Chen SQ, Akiyama H, Li ZC, Liu JP, Zhang BP - Nanoscale Res Lett (2015)

TRPL decay curves of the QDs at different excitation power. The solid curves are biexponential fits to experiment data. The inset shows temporal variation of the peak energy of the PL spectra.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4384949&req=5

Fig6: TRPL decay curves of the QDs at different excitation power. The solid curves are biexponential fits to experiment data. The inset shows temporal variation of the peak energy of the PL spectra.
Mentions: In order to further clarify the carrier transfer process and relaxation dynamics of the InGaN QDs, TRPL measurements are performed by fs impulsive excitation at room temperature. As shown in FigureĀ 6, the normalized TRPL decay curves with varied excitation densities exhibit two obvious decay stages, which are relatively faster in the early stage and slower in the extended range. The decay curves can be well fitted with a biexponential function [26]:Figure 6

Bottom Line: The integrated emission intensity increases gradually in the range from 30 to 160 K and then decreases with a further increase in temperature at high excitation intensity, while this phenomenon disappeared at low excitation intensity.Under high excitation, about 40% emission enhancement at 160 K compared to that at low temperature, as well as a higher internal quantum efficiency (IQE) of 41.1%, was observed.Using this model, the evolution of excitation-power-dependent emission intensity, shift of peak energy, and linewidth variation with elevating temperature is well explained.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics and Semiconductor Photonics Research Center, Xiamen University, 422 South Siming Road, Xiamen, 361005 P. R. China.

ABSTRACT
Strong localization effect in self-assembled InGaN quantum dots (QDs) grown by metalorganic chemical vapor deposition has been evidenced by temperature-dependent photoluminescence (PL) at different excitation power. The integrated emission intensity increases gradually in the range from 30 to 160 K and then decreases with a further increase in temperature at high excitation intensity, while this phenomenon disappeared at low excitation intensity. Under high excitation, about 40% emission enhancement at 160 K compared to that at low temperature, as well as a higher internal quantum efficiency (IQE) of 41.1%, was observed. A strong localization model is proposed to describe the possible processes of carrier transport, relaxation, and recombination. Using this model, the evolution of excitation-power-dependent emission intensity, shift of peak energy, and linewidth variation with elevating temperature is well explained. Finally, two-component decays of time-resolved PL (TRPL) with various excitation intensities are observed and analyzed with the biexponential model, which enables us to further understand the carrier relaxation dynamics in the InGaN QDs.

No MeSH data available.


Related in: MedlinePlus