Microphotoluminescence spectroscopy of single CdTe/ZnTe quantum dots grown on Si(001) substrates

Lee, Hong Seok; Rastelli, Armando; Benyoucef, M.; Ding, Fei; Kim, T W; Park, H L; Schmidt, Oliver G.

doi:10.1088/0957-4484/20/7/075705

Cited by 15 publications

(10 citation statements)

References 22 publications

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“…Importantly, the same transition sequence was observed in all other CdTe QDs reported previously, wherever the charge state of the emitting excitonic complex was identified. 14,37-41 In those reports, various experimental tools were used: PL bias dependence, 14 PL power dependence and single photon cross correlations, 37 polarization anisotropy and anisotropic exchange splitting, 38,39,41 and optical orientation. 40 In a charge-tunable device, in order to inject a next carrier, the Fermi level needs to be lifted by a certain addition energy to suppress Coulomb blockade.…”

Section: Charge Tunability and Stark Effectmentioning

confidence: 99%

Stark spectroscopy and radiative lifetimes in single self-assembled CdTe quantum dots

et al. 2011

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International audienceWe present studies on Coulomb interactions in single self-assembled CdTe quantum dots. We use a field effect structure to tune the charge state of the dot and investigate the impact of the charge state on carrier wave functions. The analysis of the quantum confined Stark shifts of four excitonic complexes allows us to conclude that the hole wave function is softer than electron wave function; i.e., it is subject to stronger modifications upon changing of the dot charge state. These conclusions are corroborated by time-resolved photoluminescence studies of recombination lifetimes of different excitonic complexes. We find that the lifetimes are notably shorter than expected for strong confinement and result from a relatively shallow potential in the valence band. This weak confinement facilitates strong hole wave function redistributions. We analyze spectroscopic shifts of the observed excitonic complexes and find the same sequence of transitions for all studied dots. We conclude that the universality of spectroscopic shifts is due to the role of Coulomb correlations stemming from strong configuration mixing in the valence band

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Section: Charge Tunability and Stark Effectmentioning

confidence: 99%

Stark spectroscopy and radiative lifetimes in single self-assembled CdTe quantum dots

et al. 2011

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“…The identification of the transitions is based on the comparison of the spectroscopic shifts with those reported in literature. In fact, whenever the charge state of a recombining complex was determined [46,54,[57][58][59][60][61], either by photon correlation measurements [46,57], by charging behavior in electric field [54,61], by optical anisotropy [57,58] or optical orientation [60], the same transition sequence was observed. A study of 200 dots corroborating this observation was reported [62].…”

Section: Single Dot Emission Spectrummentioning

confidence: 89%

Charging Effects in Self-Assembled CdTe Quantum Dots

Kłopotowski

2011

Acta Phys. Pol. A

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In this review, we summarize our achievements in controlling and understanding the charging effects in single self-assembled CdTe quantum dots. We start with analysis of the single dot emission spectrum. For excitation densities small enough to ensure only s-shell recombination, we find that for all dots (also those reported by other groups) the same transition sequence is observed. Namely, the neutral exciton recombination has the highest energy while charged exciton and biexciton transitions are redshifted. This observation remains in a stark contrast to self-assembled InGaAs dots, where charged complexes may appear also on the high energy side of the neutral exciton. We explain the universality of the transition sequence assuming domination of the Coulomb correlations over direct, single particle interactions. Furthermore, through measurement of the recombination rates, we gain access to electron and hole wave functions and their redistributions upon changing the dot occupancy. We find that the electron wave function is rather stiff, while the hole wave function is rather soft owing to enhanced correlations in the valence band. We then corroborate these conclusions with the Stark spectroscopy, where we analyze energy shifts due to electric field imposed on dots embedded in a field effect or diode structure. Finally, we use these structures to obtain controllable tuning of the charge state. We discuss different approaches to this task and find the best tuning efficiency for a structure with enhanced valence band confinement.

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“…Advances in growth technology of II-VI semiconductors permit the growth of high quality CdTe/ZnTe QDs. [8][9][10] Recently, a new method for synthesizing robust luminescent CdTe/ZnTe QDs with high photoluminescent efficiency and stability have been developed. 11 12 These QDs fulfill all the conditions for in vitro and in vivo targeted bioimaging.…”

Section: Introductionmentioning

confidence: 99%

Binding Energy of D⁰ and D⁻ Impurity Centers in CdTe/ZnTe Spherical Quantum Dot

Stojanović

Kostić²

2012

j nanosci nanotechnol

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Binding energy of neutral (D(0)) and negatively charged (D(-)) hydrogenic impurity located at the center of the CdTe/ZnTe spherical quantum dot has been investigated. Calculations are performed under the effective mass approximation on the basis of exact solution of the Schrödinger and Poisson equations. Eigenfunctions are expressed in terms of the Whittaker and Coulomb wave functions. Calculated results show that D(0) and D(-) impurity binding energies of ground 1s, 1S(1s2) and 2p, 3P(1s2p) excited states strongly depend on CdTe/ZnTe QD size if QD radius is less than one effective Bohr radius.

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Microphotoluminescence spectroscopy of single CdTe/ZnTe quantum dots grown on Si(001) substrates

Cited by 15 publications

References 22 publications

Stark spectroscopy and radiative lifetimes in single self-assembled CdTe quantum dots

Stark spectroscopy and radiative lifetimes in single self-assembled CdTe quantum dots

Charging Effects in Self-Assembled CdTe Quantum Dots

Binding Energy of D⁰ and D⁻ Impurity Centers in CdTe/ZnTe Spherical Quantum Dot

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Microphotoluminescence spectroscopy of single CdTe/ZnTe quantum dots grown on Si(001) substrates

Cited by 15 publications

References 22 publications

Stark spectroscopy and radiative lifetimes in single self-assembled CdTe quantum dots

Stark spectroscopy and radiative lifetimes in single self-assembled CdTe quantum dots

Charging Effects in Self-Assembled CdTe Quantum Dots

Binding Energy of D0 and D− Impurity Centers in CdTe/ZnTe Spherical Quantum Dot

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Binding Energy of D⁰ and D⁻ Impurity Centers in CdTe/ZnTe Spherical Quantum Dot