Excitation Transfer through Quantum Dots Measured by Microluminescence: Dependence on the Quantum Dot Density

In this paper, semiconductor quantum dot structures for mid-infrared emission were self-assembled on InP substrate by using metal–organic vapor phase epitaxy growth. The InAs quantum dots grown at different conditions have been investigated. To improve the grown quantum dot's shape, the dot density and the dot size uniformity, a two-step growth method has been used and investigated. By changing the composition of the In x Ga 1-x As matrix layer of the InAs / In x Ga 1-x As / InP quantum dot structure, emission wavelength of the InAs quantum dot structure has been extended to the longest > 2.35 μm measured at 77 K. For the narrower bandgap semiconductor InAsSb quantum dots, the emission wavelength was measured at > 2.8 μm.

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Субмонослойные квантовые точки InGaAs/GaAs, выращенные методом МОС-гидридной эпитаксии

Физика и техника полупроводников ◽

10.21883/ftp.2019.08.48011.9124 ◽

2019 ◽

Vol 53 (8) ◽

pp. 1159

Author(s):

В.Я. Алешкин ◽

Н.В. Байдусь ◽

А.А. Дубинов ◽

К.Е. Кудрявцев ◽

С.М. Некоркин ◽

...

Keyword(s):

Quantum Dots ◽

Quantum Dot ◽

Room Temperature ◽

Optical Pumping ◽

Liquid Nitrogen Temperature ◽

Stimulated Emission ◽

Threshold Power ◽

Gaas Substrates ◽

Dot Density ◽

Hydride Epitaxy

AbstractThe mode of the growth of InGaAs quantum dots by MOS-hydride epitaxy on GaAs substrates without a deviation and with a deviation of 2° is selected for laser structures emitting at wavelengths above 1.2 μm at room temperature. As a result, a quantum-dot density of 4 × 10^10 cm^–2 is achieved. Stimulated emission is observed in laser structures with seven layers of quantum dots at a wavelength of 1.06 μm at liquid-nitrogen temperature. The threshold power density of optical pumping is about 5 kW/cm^2.

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Growth and Characterization of InAs Quantum Dot Enhanced Photovoltaic Devices

MRS Proceedings ◽

10.1557/proc-1017-dd13-11 ◽

2007 ◽

Vol 1017 ◽

Cited By ~ 15

Author(s):

Seth Martin Hubbard ◽

Ryne Raffaelle ◽

Ross Robinson ◽

Christopher Bailey ◽

David Wilt ◽

...

Keyword(s):

Quantum Dots ◽

Quantum Dot ◽

Spectral Response ◽

Cell Structure ◽

Inas Quantum Dots ◽

Cell Structures ◽

Dot Density ◽

Inas Quantum Dot ◽

Iv Curves

AbstractThe growth of InAs quantum dots (QDs) by organometallic vapor phase epitaxy (OMVPE) for use in GaAs based photovoltaics devices was investigated. Growth of InAs quantum dots was optimized according to their morphology and photoluminescence using growth temperature and V/III ratio. The optimized InAs QDs had sizes near 7×40 nm with a dot density of 5(±0.5)×1010 cm-2. These optimized QDs were incorporated into GaAs based p-i-n solar cell structures. Cells with single and multiple (5x) layers of QDs were embedded in the i-region of the GaAs p-i-n cell structure. An array of 1 cm2 solar cells was fabricated on these wafers, IV curves collected under 1 sun AM0 conditions, and the spectral response measured from 300-1100 nm. The quantum efficiency for each QD cell clearly shows sub-bandgap conversion, indicating a contribution due to the QDs. Unfortunately, the overarching result of the addition of quantum dots to the baseline p-i-n GaAs cells was a decrease in efficiency. However, the addition of thin GaP strain compensating layers between the QD layers, was found to reduce this efficiency degradation and significantly enhance the subgap conversion in comparison to the un-compensated quantum dot cells.

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InNAs and GaInNAs self-assembled quantum dots and lasers grown by solid source molecular beam epitaxy

MRS Proceedings ◽

10.1557/proc-794-t3.31 ◽

2003 ◽

Vol 794 ◽

Cited By ~ 1

Author(s):

Z.Z. Sun ◽

S.F. Yoon ◽

K.C. Yew ◽

B.X. Bo

Keyword(s):

Quantum Dots ◽

Optical Properties ◽

Molecular Beam Epitaxy ◽

Quantum Dot ◽

Molecular Beam ◽

Plasma Source ◽

Nitrogen Plasma ◽

Force Microscopy ◽

Self Assembled ◽

Dot Density

ABSTRACTSelf-assembled Ga1−xInxNyAs1-y quantum dots were grown on GaAs by solid source molecular beam epitaxy (SSMBE). Introduction of N was achieved by a RF Nitrogen plasma source. Formation of quantum dots by S-K growth mode is confirmed by observation of standard 2D-3D RHEED pattern transition. Atomic force microscopy (AFM) and photoluminescence (PL) measurements were used to characterize the structure and optical properties of GaInNAs quantum dots. High GaInNAs quantum dot density (1010∼1011cm−2) was obtained for different In and N composition (0.3≤ x ≤1, y≤0.01). The effect of surface coverage on dot density, dot size, and optical properties was studied in detail. Adjusting the bandgap confinement by incorporating a GaNAs strain-reduction layer into the GaInNAs dot layer was found to extend the emission wavelength by 170nm. Room temperature pulsed operation is demonstrated for a Ga0.5In0.5N0.01As0.99 quantum dot laser emitting at ∼1.1μm.

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Optical Study of Carrier Transfer in Strain-induced Quantum Dots

MRS Proceedings ◽

10.1557/proc-417-159 ◽

1995 ◽

Vol 417 ◽

Author(s):

Yitong Gu ◽

M. D. Sturge ◽

K. Kash ◽

B. P. Van der Gaag ◽

A. S. Gozdz ◽

...

Keyword(s):

Quantum Dots ◽

Quantum Dot ◽

Quantum Well ◽

Barrier Height ◽

Intermediate State ◽

Excitation Transfer ◽

Optical Study ◽

Thermally Activated ◽

Carrier Transfer

AbstractWe have studied excitation transfer from the host quantum well to strain-confined quantum dots. We find that there is a long-lived intermediate state acting as a reservoir, holding the excitation before it is thermally activated over a barrier to reach the quantum dot. The barrier height increases monotonically with dot size.

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NiAg-graphene quantum dot-graphene hybrid with high oxidase-like catalytic activity for sensitive colorimetric detection of malathion

New Journal of Chemistry ◽

10.1039/d1nj00621e ◽

2021 ◽

Author(s):

Xu Dan ◽

Ruiyi Li ◽

Qinsheng Wang ◽

Yongqiang Yang ◽

Haiyan Zhu ◽

...

Keyword(s):

Quantum Dots ◽

Graphene Oxide ◽

Catalytic Activity ◽

Quantum Dot ◽

Colorimetric Detection ◽

Graphene Quantum Dots ◽

Functionalized Graphene ◽

Graphene Quantum Dot ◽

Nickel Silver

The paper reports the synthesis of nickel-silver-graphene quantum dot-graphene hybrid. Histidine-functionalized graphene quantum dots (His-GQDs) were bonded to graphene oxide (GO) and then combined with Ni2+ and Ag+ to form...

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Effect of Growth Temperature on the Characteristics of CsPbI3-Quantum Dots Doped Perovskite Film

Molecules ◽

10.3390/molecules26154439 ◽

2021 ◽

Vol 26 (15) ◽

pp. 4439

Author(s):

Shui-Yang Lien ◽

Yu-Hao Chen ◽

Wen-Ray Chen ◽

Chuan-Hsi Liu ◽

Chien-Jung Huang

Keyword(s):

Thin Films ◽

Thermal Stability ◽

Quantum Dots ◽

Quantum Dot ◽

Growth Temperature ◽

Electron Mobility ◽

Surface Defects ◽

Different Temperatures ◽

Pb Doping ◽

Pristine Film

In this study, adding CsPbI3 quantum dots to organic perovskite methylamine lead triiodide (CH3NH3PbI3) to form a doped perovskite film filmed by different temperatures was found to effectively reduce the formation of unsaturated metal Pb. Doping a small amount of CsPbI3 quantum dots could enhance thermal stability and improve surface defects. The electron mobility of the doped film was 2.5 times higher than the pristine film. This was a major breakthrough for inorganic quantum dot doped organic perovskite thin films.

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Carbon quantum dot-sensitized hollow TiO2 spheres for high-performance visible light photocatalysis

New Journal of Chemistry ◽

10.1039/d1nj00501d ◽

2021 ◽

Author(s):

Xianfeng Zhang ◽

Zongqun Li ◽

Shaowen Xu ◽

Yaowen Ruan

Keyword(s):

Quantum Dots ◽

Quantum Dot ◽

Visible Light ◽

Photocatalytic Degradation ◽

High Performance ◽

Carbon Quantum Dots ◽

Visible Light Photocatalysis ◽

Carbon Quantum Dot ◽

Visible Light Photocatalytic

TiO2/CQD composites were synthesized through carbon quantum dots covalently attached to the surface of hollow TiO2 spheres for visible light photocatalytic degradation of organics.

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Flexible and efficient perovskite quantum dot solar cells via hybrid interfacial architecture

Nature Communications ◽

10.1038/s41467-020-20749-1 ◽

2021 ◽

Vol 12 (1) ◽

Cited By ~ 1

Author(s):

Long Hu ◽

Qian Zhao ◽

Shujuan Huang ◽

Jianghui Zheng ◽

Xinwei Guan ◽

...

Keyword(s):

Thin Film ◽

Quantum Dots ◽

Solar Cells ◽

Quantum Dot ◽

High Performance ◽

Mechanical Stability ◽

Mechanical Adhesion ◽

Perovskite Quantum Dots ◽

Efficient Charge ◽

Photovoltaic Technologies

AbstractAll-inorganic CsPbI3 perovskite quantum dots have received substantial research interest for photovoltaic applications because of higher efficiency compared to solar cells using other quantum dots materials and the various exciting properties that perovskites have to offer. These quantum dot devices also exhibit good mechanical stability amongst various thin-film photovoltaic technologies. We demonstrate higher mechanical endurance of quantum dot films compared to bulk thin film and highlight the importance of further research on high-performance and flexible optoelectronic devices using nanoscale grains as an advantage. Specifically, we develop a hybrid interfacial architecture consisting of CsPbI3 quantum dot/PCBM heterojunction, enabling an energy cascade for efficient charge transfer and mechanical adhesion. The champion CsPbI3 quantum dot solar cell has an efficiency of 15.1% (stabilized power output of 14.61%), which is among the highest report to date. Building on this strategy, we further demonstrate a highest efficiency of 12.3% in flexible quantum dot photovoltaics.

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