Origin of photoluminescence signals obtained by picosecond-excitation correlation measurements

Chilla, J. L. A.; Buccafusca, O.; Rocca, J. J.

doi:10.1103/physrevb.48.14347

Cited by 24 publications

(22 citation statements)

References 15 publications

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“…Since the first report in 1981 [1,2], the nonlinear time-resolved photoluminescence (PL) spectroscopy technique termed picosecond or femtosecond excitation correlation (PEC or FEC) has been applied to investigate the carrier and/or exciton dynamics in various semiconductors [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. This method has the benefits of excellent time-resolution, limited only by the pulse width of the laser light used to excite the system, and a simpler experimental setup than the other ultrafast techniques.…”

Section: Introductionmentioning

confidence: 99%

“…Theoretical models of the origin of FEC signals are inevitably required for interpretation of the data. Previous studies using the excitation correlation method concerned the recombination lifetimes of carriers [1][2][3][4][5][6][7] and excitons [8], tunneling dynamics [9][10][11], bimolecular formation of excitons [12,13], and transport properties of carriers [14,15]. However, no reports have addressed the FEC signals based on the optical nonlinearity originating from the exciton-exciton annihilation process.…”

Section: Introductionmentioning

confidence: 99%

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Femtosecond excitation correlation spectroscopy of single-walled carbon nanotubes: Analysis based on nonradiative multiexciton recombination processes

2009

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We studied the nonlinear time-resolved luminescence signals due to multiexciton recombination processes in single-walled carbon nanotubes (SWNTs) using femtosecond excitation correlation (FEC) spectroscopy. From theoretical analysis of the FEC signals, we found that the FEC signals in the long time range are dominated by the single exciton decay in SWNTs, where the exciton-exciton annihilation process is efficient. Our results provide a simple method to clarify the single exciton decay dynamics in low-dimensional materials.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Femtosecond excitation correlation spectroscopy of single-walled carbon nanotubes: Analysis based on nonradiative multiexciton recombination processes

2009

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“…In typical TR NL PL measurements using ultrashort laser pulses, the detected signal, although a function of the delay between the two exciting pulses, is actually integrated in real time for a period T corresponding to the repetition rate of the pulsed laser. 6,7 If T is larger than the carrier lifetime, the carrier density changes from its value at excitation to zero during T. Thus the measured TR NL PL signal is in fact an integration over the effects of change in the carrier density with time during T before the next pair of pulses can excite the sample. The TR NL PL measurements therefore are not best suited to investigate density dependent nonlinearities in the PL spectra.…”

Section: Methodsmentioning

confidence: 99%

“…Thus, the NL PL signal is negative ͑positive͒ for a sublinear ͑superlinear͒ dependence of the PL on I. Recently, by using picosecond laser pulses, several time-resolved ͑TR͒ NL PL measurements were made [6][7][8] to study carrier and exciton dynamics in semiconductors. These measurements were also used to resolve closely spaced PL lines with different nonlinearities.…”

Section: Introductionmentioning

confidence: 99%

Intensity correlated nonlinear photoluminescence spectra in undoped andp-doped GaAs and GaAs quantum wells

et al. 2002

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We study the line shapes and excitation density dependence of the intensity correlated nonlinear ͑NL͒ photoluminescence ͑PL͒ spectra due to excitons and free electron-hole pairs in molecular beam epitaxy grown undoped and p-doped GaAs and GaAs quantum wells. The laser excitation intensity ͑I͒ is varied by nearly three orders of magnitude. The NL PL spectra show negative peaks at energies corresponding to free and bound excitons as I increases. These peaks do not diminish, but continue to increase with I up to the highest value of I used.

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“…19 These relationships show that close to P c , PLII is basically determined by the variation of IIr with pressure ͑or ⌬E͒ and above P c saturates at the value of IInr . Using values of Aϭ3 meV, ⌬Eϭ5 meV at 1.2 GPa, 4 Ir Ϸ1.4 ns 19 and IInr ϭ400 ps, we calculated PLII ϭ360 ps. The factor of 2 difference between the calculated and measured PLII suggests that ⌬E may be smaller than 5 meV.…”

mentioning

confidence: 95%

Effect of indirect Γ-L and Γ-X transfer on the carrier dynamics of InGaP/InAlP multiple quantum wells

Menoni

Buccafusca

Marconi

et al. 1997

Applied Physics Letters

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Indirect ⌫-L scattering within the well, and real space carrier transfer to the barrier X 1c states are shown to significantly affect the carrier dynamics in In 0.48 Ga 0.52 P/In 0.5 Al 0.5 P multiple quantum wells. When carriers transfer to the indirect states occurs, the carrier dynamics is modified by the slow return of the carriers from the low mobility states to the well. As a result, the absorption recovery time increases by almost an order of magnitude. Carrier transfer to the indirect states also increases the carrier lifetime to values characteristic of indirect recombination. © 1997 American Institute of Physics. ͓S0003-6951͑97͒03001-5͔In 0.48 Ga 0.52 P/͑Al x Ga 1Ϫx ) 0.5 In 0.5 P multiple quantum wells ͑MQWs͒ are commonly used in the design of visible semiconductor lasers operating around 650 nm. 1 In the last few years, an effort in the design of visible laser diodes has been directed towards obtaining devices operating at wavelengths as short as 630 nm.2 However, these devices have been found to have higher threshold current and higher temperature sensitivity than those operating at longer wavelength, characteristics which have been associated with poor electron confinement. 2Several factors can limit the electron confinement, such as a small conduction band discontinuity, or carrier transfer to indirect valleys. In the visible heterostructures the former can be essentially ruled out, as the conduction band discontinuity in the In 0.48 Ga 0.52 P/͑Al x Ga 1Ϫx ) 0.5 In 0.5 P system has been measured to be 70% of the direct band gap difference between the well and barrier materials for a wide range of Al compositions x. 3,4 Scattering to the indirect valleys on the other hand, can significantly affect the carrier confinement, providing a leakage channel for carriers to transfer to the high effective mass L 1c or X 1c valleys. In bulk unstrained In 0.48 Ga 0.52 P, L 1c is approximately 0.2 eV below X 1c and can be accessible from ⌫ 1c by injecting carriers with excess energies of ϳ0.1 eV, the ⌫ 1c -L 1c separation. 5 In MQWs even lower energies are sufficient as the separation of the MQW ground state (⌫ 1e ) and L 1c is further reduced with increased carrier confinement. In addition, real space carrier transfer to the indirect X 1c valleys in the barrier (X 1c b ) may also occur in the In 0.52 Ga 0.48 P/͑Al x Ga 1Ϫx ) 0.5 In 0.5 P MQWs when the barrier composition x is selected to be larger than 0.5 and the barrier becomes indirect. The associated decrease in the carrier mobility that accompanies this transfer has been shown to have dramatic effects on the threshold current of In 0.48 Ga 0.52 P/ (Al x Ga 1Ϫx ) 0.5 In 0.5 P lasers. 6 In this letter we present evidence of the important of ⌫-L scattering and real space ⌫-X carrier transfer on the carrier dynamics of In 0.48 Ga 0.5 P/In 0.5 Al 0.5 P MQWs and show that when carrier transfer to indirect states occurs, the carrier dynamics becomes dominated by the slow return of the carriers from the low mobility states to the well. As a result, the absorptio...

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Origin of photoluminescence signals obtained by picosecond-excitation correlation measurements

Cited by 24 publications

References 15 publications

Femtosecond excitation correlation spectroscopy of single-walled carbon nanotubes: Analysis based on nonradiative multiexciton recombination processes

Femtosecond excitation correlation spectroscopy of single-walled carbon nanotubes: Analysis based on nonradiative multiexciton recombination processes

Intensity correlated nonlinear photoluminescence spectra in undoped andp-doped GaAs and GaAs quantum wells

Effect of indirect Γ-L and Γ-X transfer on the carrier dynamics of InGaP/InAlP multiple quantum wells

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