Role of quantum confinement in luminescence efficiency of group IV nanostructures

Barbagiovanni, Eric G.; Lockwood, D. J.; Rowell, N. L.; Filho, R. N. Costa; Berbézier, Isabelle; Amiard, Guillaume; Favre, Luc; Ronda, A.; Faustini, Marco; Grosso, David

doi:10.1063/1.4863397

Cited by 23 publications

(19 citation statements)

References 22 publications

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“…which can be depicted by a decreasing exponential curve. Similar qualitative results have been reported 5,26,[35][36][37][38] , but the results differ slightly with calculation method. For example, the standard DFT with LDA functional 36 and the empirical pseudopotential method (EMP) for oxidized Si-QDs showed a linearly dependent gap change.…”

Section: Calculation Methodssupporting

confidence: 87%

Luminescence mechanism in hydrogenated silicon quantum dots with a single oxygen ligand

Shen

Wang

et al. 2021

Nanoscale Adv.

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Section: Calculation Methodssupporting

confidence: 87%

Luminescence mechanism in hydrogenated silicon quantum dots with a single oxygen ligand

Shen

Wang

et al. 2021

Nanoscale Adv.

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“…4,26,27 In addition, both theoretical and experimental studies suggest a reduction of the effective mass (EM) in confined structures with respect to the bulk values. [28][29][30] Still, the QD dimension as well as the matrix-nanostructure interface play paramount roles in the modification of EM. Very recently, a reduction of the carrier EM was experimentally observed for Si nanocrystals embedded in oxide and nitride matrices by EELS analysis.…”

Section: Introductionmentioning

confidence: 99%

The role of the interface in germanium quantum dots: when not only size matters for quantum confinement effects

et al. 2015

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Quantum confinement (QC) typically assumes a sharp interface between a nanostructure and its environment, leading to an abrupt change in the potential for confined electrons and holes. When the interface is not ideally sharp and clean, significant deviations from the QC rule appear and other parameters beyond the nanostructure size play a considerable role. In this work we elucidate the role of the interface on QC in Ge quantum dots (QDs) synthesized by rf-magnetron sputtering or plasma enhanced chemical vapor deposition (PECVD). Through a detailed electron energy loss spectroscopy (EELS) analysis we investigated the structural and chemical properties of QD interfaces. PECVD QDs exhibit a sharper interface compared to sputter ones, which also evidences a larger contribution of mixed Ge-oxide states. Such a difference strongly modifies the QC strength, as experimentally verified by light absorption spectroscopy. A large size-tuning of the optical bandgap and an increase in the oscillator strength occur when the interface is sharp. A spatially dependent effective mass (SPDEM) model is employed to account for the interface difference between Ge QDs, pointing out a larger reduction in the exciton effective mass in the sharper interface case. These results add new insights into the role of interfaces on confined systems, and open the route for reliable exploitation of QC effects.

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“…However, the C (730 nm) and D (810 nm) bands were related to band-to-band transitions in Si-ncs due to the quantum confinement effects (QCE) [ 5 ], where their emission energy depended on their size. It was previously shown that the emission band can range from the near infrared to the blue by reducing the size of Si-ncs [ 41 ]. For the case of Si-ncs embedded in a SiO 2 matrix, the energy varies according to the following expression [ 42 ]: E g (d ncs ) = E g0 + [5.83/(d ncs ) 1.78 ] where E g0 is the bulk silicon bandgap in eV, d ncs is the Si-ncs diameter in nm and 5.83 is the confinement parameter.…”

Section: Resultsmentioning

confidence: 99%

Effect of the Graded Silicon Content in SRN/SRO Multilayer Structures on the Si Nanocrystals and Si Nanopyramids Formation and Their Photoluminescence Response

et al. 2021

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Two multilayer (ML) structures, composed of five layers of silicon-rich oxide (SRO) with different Si contents and a sixth layer of silicon-rich nitride (SRN), were deposited by low pressure chemical vapor deposition. These SRN/SRO MLs were thermally annealed at 1100 °C for 180 min in ambient N2 to induce the formation of Si nanostructures. For the first ML structure (MLA), the excess Si in each SRO layer was about 10.7 ± 0.6, 9.1 ± 0.4, 8.0 ± 0.2, 9.1 ± 0.3 and 9.7 ± 0.4 at.%, respectively. For the second ML structure (MLB), the excess Si was about 8.3 ± 0.2, 10.8 ± 0.4, 13.6 ± 1.2, 9.8 ± 0.4 and 8.7 ± 0.1 at.%, respectively. Si nanopyramids (Si-NPs) were formed in the SRO/Si substrate interface when the SRO layer with the highest excess silicon (10.7 at.%) was deposited next to the MLA substrate. The height, base and density of the Si-NPs was about 2–8 nm, 8–26 nm and ~6 × 1011 cm−2, respectively. In addition, Si nanocrystals (Si-ncs) with a mean size of between 3.95 ± 0.20 nm and 2.86 ± 0.81 nm were observed for the subsequent SRO layers. Meanwhile, Si-NPs were not observed when the excess Si in the SRO film next to the Si-substrate decreased to 8.3 ± 0.2 at.% (MLB), indicating that there existed a specific amount of excess Si for their formation. Si-ncs with mean size of 2.87 ± 0.73 nm and 3.72 ± 1.03 nm were observed for MLB, depending on the amount of excess Si in the SRO film. An enhanced photoluminescence (PL) emission (eight-fold more) was observed in MLA as compared to MLB due to the presence of the Si-NPs. Therefore, the influence of graded silicon content in SRN/SRO multilayer structures on the formation of Si-NPs and Si-ncs, and their relation to the PL emission, was analyzed.

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Role of quantum confinement in luminescence efficiency of group IV nanostructures

Cited by 23 publications

References 22 publications

Luminescence mechanism in hydrogenated silicon quantum dots with a single oxygen ligand

Luminescence mechanism in hydrogenated silicon quantum dots with a single oxygen ligand

The role of the interface in germanium quantum dots: when not only size matters for quantum confinement effects

Effect of the Graded Silicon Content in SRN/SRO Multilayer Structures on the Si Nanocrystals and Si Nanopyramids Formation and Their Photoluminescence Response

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