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

Normalized integrated PL intensity as a function of 1/Tfor the InGaN QD emission.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig3: Normalized integrated PL intensity as a function of 1/Tfor the InGaN QD emission.

Mentions: The integrated emission intensities of the QD sample are given in Figure 3 as a function of the reciprocal of temperature. The temperature-dependent emission intensities were normalized by the integrated emission intensity at 5 K. It is quite significant to notice that an anomalous enhanced emission appears over a temperature range of 30 to 160 K at high excitation intensity. However, for the weak excitation, the emission intensity decreases monotonously with a small “uplift” in the same temperature range and then decreases more rapidly with further increase of the temperature. In the former case, the maximum emission intensity at 160 K is enhanced by 40% in comparison to that at low temperature. Beside, a high internal quantum efficiency (IQE) of approximately 41% is obtained by the ratio of emission intensity at room temperature and that at 5 K, assuming that the radiative recombination is dominant at sufficiently low temperature.Figure 3


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)

Normalized integrated PL intensity as a function of 1/Tfor the InGaN QD emission.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig3: Normalized integrated PL intensity as a function of 1/Tfor the InGaN QD emission.
Mentions: The integrated emission intensities of the QD sample are given in Figure 3 as a function of the reciprocal of temperature. The temperature-dependent emission intensities were normalized by the integrated emission intensity at 5 K. It is quite significant to notice that an anomalous enhanced emission appears over a temperature range of 30 to 160 K at high excitation intensity. However, for the weak excitation, the emission intensity decreases monotonously with a small “uplift” in the same temperature range and then decreases more rapidly with further increase of the temperature. In the former case, the maximum emission intensity at 160 K is enhanced by 40% in comparison to that at low temperature. Beside, a high internal quantum efficiency (IQE) of approximately 41% is obtained by the ratio of emission intensity at room temperature and that at 5 K, assuming that the radiative recombination is dominant at sufficiently low temperature.Figure 3

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