Quantum Dots Prepared by Droplet Epitaxial Method

Nemcsics, Ákos

doi:10.5772/60823

Cited by 8 publications

(4 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The growth mechanism of InGaN microplates has been extensively studied [ 16 , 18 , 24 , 30 , 31 , 32 , 33 , 34 , 35 ], while the CL properties of full-composition-graded In x Ga 1−x N film are rarely reported, especially InGaN microplates. We found that the CL luminescence intensity of microplates inside was significantly weaker than microplates outside.…”

Section: Resultsmentioning

confidence: 99%

Cathodoluminescence Spectroscopy in Graded InxGa1−xN

et al. 2022

View full text Add to dashboard Cite

InGaN materials are widely used in optoelectronic devices due to their excellent optical properties. Since the emission wavelength of the full-composition-graded InxGa1−xN films perfectly matches the solar spectrum, providing a full-spectrum response, this makes them suitable for the manufacturing of high-efficiency optoelectronic devices. It is extremely important to study the optical properties of materials, but there are very few studies of the luminescence of full-composition-graded InxGa1−xN ternary alloy. In this work, the optical properties of full-composition-graded InxGa1−xN films are studied by cathodoluminescence (CL). The CL spectra with multiple luminescence peaks in the range of 365–1000 nm were acquired in the cross-sectional and plan-view directions. The CL spectroscopy studies were carried out inside and outside of microplates formed under the indium droplets on the InGaN surface, which found that the intensity of the light emission peaks inside and outside of microplates differed significantly. Additionally, the paired defects structure is studied by using the spectroscopic method. A detailed CL spectroscopy study paves the way for the growth and device optimization of high-quality, full-composition-graded InxGa1−xN ternary alloy materials.

show abstract

Section: Resultsmentioning

confidence: 99%

Cathodoluminescence Spectroscopy in Graded InxGa1−xN

et al. 2022

View full text Add to dashboard Cite

show abstract

“…A few proposed solutions can mitigate the carrier leakage problem in the SK QDs, including dot-in-a-well approach [ 16 ], graded-index separate-confinement-heterostructure [ 17 ], stacking many QD layers [ 18 ], applying the tunnel-injection scheme [ 19 ], or fabricating QDs without the WL. For the latter, one can use the droplet epitaxy (DE) technique in which a group-III element droplet is deposited directly on a substrate undergoing subsequent re-crystallization under deposition of a group-V ad-atoms, spontaneously forming a nanometer-sized island [ 20 ]. First applied to the formation of GaAs QDs on ZnSe substrate [ 21 ], later successfully employed to other semiconductor systems, including the InAs/InP one [ 22 ].…”

Section: Introductionmentioning

confidence: 99%

Optical Properties of Site-Selectively Grown InAs/InP Quantum Dots with Predefined Positioning by Block Copolymer Lithography

et al. 2021

View full text Add to dashboard Cite

The InAs/InP quantum dots (QDs) are investigated by time-integrated (PL) and time-resolved photoluminescence (TRPL) experiments. The QDs are fabricated site-selectively by droplet epitaxy technique using block copolymer lithography. The estimated QDs surface density is ∼1.5 × 1010 cm−2. The PL emission at T=300 K is centered at 1.5 μm. Below T=250 K, the PL spectrum shows a fine structure consisting of emission modes attributed to the multimodal QDs size distribution. Temperature-dependent PL reveals negligible carrier transfer among QDs, suggesting good carrier confinement confirmed by theoretical calculations and the TRPL experiment. The PL intensity quench and related energies imply the presence of carrier losses among InP barrier states before carrier capture by QD states. The TRPL experiment highlighted the role of the carrier reservoir in InP. The elongation of PL rise time with temperature imply inefficient carrier capture from the reservoir to QDs. The TRPL experiment at T=15 K reveals the existence of two PL decay components with strong dispersion across the emission spectrum. The decay times dispersion is attributed to different electron-hole confinement regimes for the studied QDs within their broad distribution affected by the size and chemical content inhomogeneities.

show abstract

“…Much attention has been paid to the crystallization processes which allow modifying the final shape of droplets thus forming various types of nanostructures and complexes [26,[28][29][30][31][32][33][34]. Nucleation and growth of islands during deposition of group III atoms, which has no less significance, is poorly investigated because droplet epitaxy at a first stage is considered to be realized according to the wellstudied Volmer-Weber growth mechanism [26,[35][36][37]. However, there is a number of questions and contradictions which are observed by different experimental studies.…”

Section: Introductionmentioning

confidence: 99%

“…Finally, it should be concluded that the nucleation mechanism during In/GaAs(001) droplet epitaxy still remains unclear. Droplets are naturally considered to be generated by the Volmer-Weber growth mode because the binding energy among metallic adatoms is greater than to the substrate surface [26,37]. However, it runs counter to the observation of critical thickness dependent on the substrate temperature [39].…”

Section: Introductionmentioning

confidence: 99%

Mechanism of nucleation and critical layer formation during In/GaAs droplet epitaxy

Balakirev¹,

Солодовник²,

Eremenko³

et al. 2019

Nanotechnology

View full text Add to dashboard Cite

Fabrication of A III B V nanostructures by droplet epitaxy has many advantages over other epitaxial techniques. Although various characteristics of the growth by droplet epitaxy have been thoroughly studied for both lattice-matched and mismatched systems, little is known about physical processes hindering the formation of small size InAs/GaAs nanostructure arrays with low density and thin wetting layer. In this paper, we experimentally demonstrate that the indium droplet diameter can be reduced by decreasing the deposition time, but this reduction is limited by a critical thickness of droplet formation dependent on the substrate temperature. Using the kinetic Monte Carlo model, we propose a mechanism considering that the droplet formation begins when the system overcomes a barrier determined by the substrate attraction. As a result of physical and chemical balancing between adatom aggregation and substrate wetting, this attraction becomes weaker with increasing either temperature or deposition amount, which leads to the critical layer formation and subsequent nucleation. Using this mechanism, it is possible to provide a wide control over the nanostructure growth which is especially important at high temperatures when the processes of the island ripening are particularly intensive.

show abstract

Quantum Dots Prepared by Droplet Epitaxial Method

Cited by 8 publications

References 60 publications

Cathodoluminescence Spectroscopy in Graded InxGa1−xN

Cathodoluminescence Spectroscopy in Graded InxGa1−xN

Optical Properties of Site-Selectively Grown InAs/InP Quantum Dots with Predefined Positioning by Block Copolymer Lithography

Mechanism of nucleation and critical layer formation during In/GaAs droplet epitaxy

Contact Info

Product

Resources

About