Optical Nmr From Single Quantum Dots

1996 ◽  
Vol 442 ◽  
Author(s):  
S. W. Brown ◽  
T. A. Kennedy ◽  
D. Gammon
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Quantum Wells ◽  
Optical Pumping ◽  
Nuclear Orientation ◽  
Energy Levels ◽  
Zeeman Splitting ◽  
Single Quantum ◽  
Interface Fluctuations ◽  
20 Nm

AbstractWe have observed nuclear magnetic resonance (NMR) signatures from constituent Ga and As nuclei in single GaAs quantum dots formed by interface fluctuations in GaAs/AlGaAs quantum wells. Orientation of the nuclear spin system by optical pumping causes an Overhauser shift in the excitonic energy levels proportional to the degree of nuclear orientation. NMR was detected by monitoring changes in the combined Overhauser plus Zeeman splitting of an exciton localized in a single quantum dot as the RF frequency was swept through a nuclear resonance. The NMR signals originate from ∼105 nuclei in the quantum dot — (20 nm)3 volume - representing an increase in sensitivity of five orders of magnitude over previous optical NMR measurements and thirteen orders of magnitude over conventional NMR. The data were fit to Lorentzian lineshapes, giving 75As linewidths on the order of 20 kHz.

Modeling of elastic, piezoelectric and optical properties of vertically correlated GaN/AlN quantum dots

2004 ◽  
Vol 831 ◽  
Author(s):  
Sławomir P. Łepkowski ◽  
Grzegorz Jurczak ◽  
Paweł Dłużewski ◽  
Tadeusz Suski
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Quantum Dot ◽  
Quantum Wells ◽  
Electrostatic Potential ◽  
Barrier Width ◽  
Base Diameter ◽  
Transition Energies ◽  
Band Transition ◽  
Hexagonal Pyramid

ABSTRACTWe theoretically investigate elastic, piezoelectric and optical properties of wurtzite GaN/AlN quantum dots, having hexagonal pyramid-shape, stacked in a multilayer. We show that the strain existing in quantum dots and barriers depends significantly on the distance between the dots i.e. on the width of AlN barriers. For typical QDs, having the base diameter of 19.5nm, the drop of the electrostatic potential in the quantum dot region slightly decreases with decreasing of the barrier width. This decrease is however much smaller for QDs than for superlattice of GaN/AlGaN quantum wells, with thickness similar to the height of QDs. Consequently, the band-to-band transition energies in the vertically correlated GaN/AlN QDs show unexpected, rather weak dependence on the width of AlN barriers. Increasing the QD base diameter leads to stronger decreasing dependence of the band-to-band transition energies vs. the width of AlN barriers, similar to that observed for superlattieces of QWs.

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

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.

Zirconium ion-mediated assembly of single quantum dot-based nanosensor for kinases assay

2021 ◽  
Author(s):  
Yue-Ying Li ◽  
Qian Liu ◽  
Lin Cui ◽  
Wenjing Liu ◽  
Jian-Ge Qiu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Protein Kinases ◽  
Single Quantum ◽  
Accurate Detection ◽  
Single Quantum Dots ◽  
Single Quantum Dot

We demonstrate the zirconium ion-mediated assembly of single quantum dots (QD)-based nanosensor for accurate detection of protein kinases (PKA) and polynucleotide kinases (PNK). This nanosensor is very sensitive with a...

LEVEL STABILITY OF THE QUANTUM DOTS WITH IMPURITY

1999 ◽  
Vol 13 (27) ◽  
pp. 977-981 ◽  
Author(s):  
YUNG-SHENG HUANG ◽  
SY-SANG LIAW
Keyword(s):  
Quantum Dots ◽  
Simple Model ◽  
Quantum Dot ◽  
Band Gap ◽  
Energy Levels ◽  
The Stability ◽  
Spherical Potential

An atom located at the center of the constant spherical potential is adopted as a simple model for a quantum dot with impurity. We find that, under this model, the stability of the energy levels of a quantum dot with impurity can be controlled by adjusting either the size or the band gap of the quantum dot.

LIGHT EMISSION, ABSORPTION AND AMPLIFICATION IN InAs/GaAs QUANTUM DOTS AND GaAs/AlGaAs QUANTUM WELLS RESULTING FROM OPTICAL PUMPING

2007 ◽  
Vol 06 (03n04) ◽  
pp. 241-244 ◽  
Author(s):  
D. A. FIRSOV ◽  
L. E. VOROBJEV ◽  
M. A. BARZILOVICH ◽  
V. YU. PANEVIN ◽  
I. V. MIKHAYLOV ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Quantum Wells ◽  
Light Absorption ◽  
Optical Pumping ◽  
Light Emission ◽  
Optical Excitation ◽  
Ground Level ◽  
Infrared Light ◽  
Mid Infrared ◽  
Gaas Quantum Dot

Optical phenomena in quantum dot and quantum well nanostructures aimed at the development of mid-infrared lasers based on intraband electron transitions are investigated in the conditions of interband optical pumping. Evolution of photoluminescence spectra and interband light absorption with intensity of interband optical excitation is investigated in InAs / GaAs quantum dot structures. Optically induced intersubband mid-infrared light absorption is studied in undoped tunnel-coupled GaAs / AlGaAs quantum wells. The stabilization of the electron concentration at the ground level of tunnel-coupled quantum wells under increasing pumping level is established.

The influence of continuous vs. pulsed laser excitation on single quantum dot photophysics

2014 ◽  
Vol 16 (47) ◽  
pp. 25723-25728 ◽  
Author(s):  
Julie A. Smyder ◽  
Amanda R. Amori ◽  
Michael Y. Odoi ◽  
Harry A. Stern ◽  
Jeffrey J. Peterson ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Laser Excitation ◽  
Pulsed Laser ◽  
Single Quantum ◽  
Single Quantum Dots ◽  
Single Quantum Dot ◽  
Similarities And Differences ◽  
Continuous Excitation

Important similarities and differences between pulsed and continuous excitation on the fluorescence dynamics of single quantum dots were discovered.

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