Confinement effects in PbSe quantum wells and nanocrystals

Allan, G.; Delerue, Christophe

doi:10.1103/physrevb.70.245321

Cited by 267 publications

(348 citation statements)

References 41 publications

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“…The zero of energy is located at the top of the valence band. [11] ticle size. Finally, one has to be aware that the second derivative itself can create artefacts.…”

Section: Resultsmentioning

confidence: 99%

“…The assignment of the optical transitions is subject to considerable debate in the literature. [1,[10][11][12][13] This debate largely focuses on the assignment of the "second" peak in the absorption spectrum, labelled b here. Based on theoretical calculations of the energy levels and experimental work, this feature has previously been assigned to the 1S h -1P e (or 1P h -1S e ) transition.…”

Section: Resultsmentioning

confidence: 99%

“…Based on theoretical calculations of the energy levels and experimental work, this feature has previously been assigned to the 1S h -1P e (or 1P h -1S e ) transition. [11,14] However, these transitions are optically forbidden and are expected to be very weak. Liljeroth et al were able to measure the density of states of single PbSe nanocrystals directly using scanning tunnelling spectroscopy and suggested that transition b corresponds to the 1P h -1P e transition.…”

Section: Resultsmentioning

confidence: 99%

“…[11] The calculated spectrum is plotted together with the experimental spectrum of PbSe QDs with a diameter of 6.8 nm (see Figure 3). In energy, this is the best matching experimental spectrum that we have measured compared to the calculated spectrum.…”

Section: Resultsmentioning

confidence: 99%

“…First, the assignment of the multiple features (up to 11) in the absorption spectrum of highly monodisperse PbSe QDs is discussed and compared to calculated spectra of PbSe QDs that were recently published. [1,11] Next, the size dependence of the energy of the various transitions is analyzed for 16 different sizes of PbSe QDs, ranging from 3.4 to 10.9 nm. It follows that the higher-energy transitions can be assigned to optical transitions at a different point in the Brillouin zone than the lower-energy transitions.…”

Section: Introductionmentioning

confidence: 99%

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Optical Investigation of Quantum Confinement in PbSe Nanocrystals at Different Points in the Brillouin Zone

Koole

Allan

Delerue

et al. 2008

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We present detailed investigations on the optical properties of PbSe nanocrystals. The absorption spectra of monodisperse, quasispherical nanocrystals exhibit sharp features as a result of distinct optical transitions. To study the size dependence, absorption spectra of nanocrystals ranging from 3.4 to 10.9 nm in diameter are analysed and a total of 11 distinct optical transitions are identified. The assignment of the various optical transitions is discussed and compared to theoretically calculated transition energies. By plotting all transitions as a function of nanocrystal size (D) we find that the energy (E) changes with the following relationship E / D À1.5 for the lowest energy transitions. The transition energy extrapolates to approximately 0.3 eV for infinite crystal size, in agreement with the bandgap of bulk PbSe at the L-point in the Brillouin zone. In addition, high-energy transitions are observed, which extrapolate to 1.6 eV for infinite crystal size, which is in good agreement with the bulk bandgap of PbSe at the S-point in the Brillouin zone. Tight-binding calculations confirm that the high-energy transitions originate from the S-point in the Brillouin zone. The S-character of the high-energy transitions may be of importance to explain the mechanism behind multiple exciton generation in PbSe nanocrystals.

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“…The zero of energy is located at the top of the valence band. [11] ticle size. Finally, one has to be aware that the second derivative itself can create artefacts.…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Optical Investigation of Quantum Confinement in PbSe Nanocrystals at Different Points in the Brillouin Zone

Koole

Allan

Delerue

et al. 2008

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The Interaction between Quantum Dots and Graphene: The Applications in Graphene‐Based Solar Cells and Photodetectors

Feng

et al. 2018

Adv Funct Materials

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Graphene with a series of neoteric electronic and optical properties is an intriguing building block for optoelectronic devices. Over the past decade, graphene‐based solar cells (SCs) and photodetectors (PDs) which can convert light signals to electrical signals have received burgeoning exploration. However, limited light absorption hampers the performance of these devices. Quantum dots (QDs) possess a strong confinement effect, a large exciton energy, and long exciton lifetime, enhancing the interaction between incident light and graphene. Especially, as the density of states near the Dirac point of graphene is ultralow, it is easy to modify the Fermi level of graphene by inserting quantum dots at the interface between graphene and light, thereby enhancing the performance of graphene‐based optoelectronic devices. The characteristics of QDs and crucial physical mechanisms of the interaction and energy transfer in QDs/graphene nanohybrids are systematically addressed. The factors influencing the efficiency of energy transfer are also analyzed quantitatively. Moreover, the experimental process of QD‐enhanced technologies for SCs, photoconductors, phototransistors, and photodiode PDs is reviewed. Eventually, a conclusion is given and the remaining challenges and future development for QDs/2D materials hybrid systems is discussed. Possible steps toward large‐scale commercial applications and integration into optoelectronic networks are suggested.

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25th Anniversary Article: Colloidal Quantum Dot Materials and Devices: A Quarter‐Century of Advances

et al. 2013

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Colloidal quantum dot (CQD) optoelectronics offers a compelling combination of low-cost, large-area solution processing, and spectral tunability through the quantum size effect. Since early reports of size-tunable light emission from solution-synthesized CQDs over 25 years ago, tremendous progress has been made in synthesis and assembly, optical and electrical properties, materials processing, and optoelectronic applications of these materials. Here some of the major developments in this field are reviewed, touching on key milestones as well as future opportunities.

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Confinement effects in PbSe quantum wells and nanocrystals

Cited by 267 publications

References 41 publications

Optical Investigation of Quantum Confinement in PbSe Nanocrystals at Different Points in the Brillouin Zone

Optical Investigation of Quantum Confinement in PbSe Nanocrystals at Different Points in the Brillouin Zone

The Interaction between Quantum Dots and Graphene: The Applications in Graphene‐Based Solar Cells and Photodetectors

25th Anniversary Article: Colloidal Quantum Dot Materials and Devices: A Quarter‐Century of Advances

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