scholarly journals Бимодальность в спектрах электролюминесценции InGaAs квантовых яма-точек

2022 ◽  
Vol 56 (1) ◽  
pp. 97
Author(s):  
A.A. Харченко ◽  
А.М. Надточий ◽  
А.А. Серин ◽  
С.А. Минтаиров ◽  
Н.А. Калюжный ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Active Region ◽  
Quantum Well ◽  
Ground State ◽  
Polarized Light ◽  
Temperature Decrease ◽  
Temperature Range ◽  
Polarized Emission ◽  
Different Types ◽  
Two Peaks

The electroluminescence spectra of waveguiding structures based on quantum well-dots were investigated with polarization resolution in the temperature range of 60−300 K. It is found that the ground state emission consists of two peaks with different degrees of TE-polarization and these peaks are getting closer with temperature decrease. We attribute the bimodality to the existence of two different types of nanoobjects in the active region: the quantum well-dots, which have partially TE-polarized emission, and quantum dots emitting almost fully TE-polarized light.

scholarly journals The issue of 0D-like ground state isolation in GaAs- and InP-based coupled quantum dots-quantum well systems

2017 ◽  
Vol 906 ◽  
pp. 012019 ◽  
Author(s):  
M. Syperek ◽  
J. Andrzejewski ◽  
W. Rudno-Rudziński ◽  
A. Maryński ◽  
G. Sȩk ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Well ◽  
Ground State ◽  
Coupled Quantum Dots

scholarly journals Investigation of optical properties of In(Ga)As/GaAs mesa structures with active region based on quantum wells, quantum dots, and quantum well-dots

2019 ◽  
Vol 1410 ◽  
pp. 012157 ◽  
Author(s):  
A S Dragunova ◽  
N V Kryzhanovskaya ◽  
M V Maximov ◽  
S A Mintairov ◽  
N A Kalyuzhnyy ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Active Region ◽  
Quantum Well ◽  
Quantum Wells

scholarly journals Output power of multilayered InGaAs/GaAs quantum well-dot microdisk lasers

2021 ◽  
Vol 2086 (1) ◽  
pp. 012081
Author(s):  
N A Fominykh ◽  
E I Moiseev ◽  
Ju A Guseva ◽  
M V Maximov ◽  
A I Lihachev ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Active Region ◽  
Quantum Well ◽  
Output Power ◽  
Optical Power ◽  
Threshold Current ◽  
Sudden Drop ◽  
Output Optical Power ◽  
Number Of Layers ◽  
Microdisk Lasers

Abstract We studied the output optical power of microdisk lasers with InGaAs/GaAs quantum dots active region. An increase in the number of layers in the active region in the waveguide from 2 to 6 leads to increase in the peak output optical power due probably to increase of the gain. We also observe a corresponding increase of the threshold current due to the increase on the transparence current. The maximal optical power is achieved for structure with 6 layers at approximately 60 mA injection current. Further increase of the number of the QD layers to 10 results in increase of the threshold current and sudden drop of the output power.

Low-Temperature Operation of Green, Blue and UV InGaN/GaN Multiple-Quantum-Well Light-Emitting Diodes

2003 ◽  
Vol 764 ◽  
Author(s):  
X. A. Cao ◽  
S. F. LeBoeuf ◽  
J. L. Garrett ◽  
A. Ebong ◽  
L. B. Rowland ◽  
...  
Keyword(s):  
Quantum Well ◽  
Light Emitting Diodes ◽  
Multiple Quantum Well ◽  
Light Output ◽  
Localized States ◽  
Multiple Quantum ◽  
Nonradiative Recombination ◽  
Light Emitting ◽  
Temperature Range ◽  
Green Leds

Absract:Temperature-dependent electroluminescence (EL) of InGaN/GaN multiple-quantum-well light-emitting diodes (LEDs) with peak emission energies ranging from 2.3 eV (green) to 3.3 eV (UV) has been studied over a wide temperature range (5-300 K). As the temperature is decreased from 300 K to 150 K, the EL intensity increases in all devices due to reduced nonradiative recombination and improved carrier confinement. However, LED operation at lower temperatures (150-5 K) is a strong function of In ratio in the active layer. For the green LEDs, emission intensity increases monotonically in the whole temperature range, while for the blue and UV LEDs, a remarkable decrease of the light output was observed, accompanied by a large redshift of the peak energy. The discrepancy can be attributed to various amounts of localization states caused by In composition fluctuation in the QW active regions. Based on a rate equation analysis, we find that the densities of the localized states in the green LEDs are more than two orders of magnitude higher than that in the UV LED. The large number of localized states in the green LEDs are crucial to maintain high-efficiency carrier capture at low temperatures.

Acetylene chemisorption at palladium: Effect of temperature and structure of the surface

1984 ◽  
Vol 49 (6) ◽  
pp. 1448-1458
Author(s):  
Josef Kopešťanský
Keyword(s):  
Work Function ◽  
Atomic Hydrogen ◽  
Effect Of Temperature ◽  
Thermally Stable ◽  
Template Effect ◽  
Temperature Range ◽  
Adsorbed Layers ◽  
Different Types ◽  
Adsorption Complexes ◽  
Low Coverage

The effect of temperature and structure of the palladium surfaces on acetylene chemisorption was studied along with the interaction of the adsorbed layers with molecular and atomic hydrogen. The work function changes were measured and combined with the volumetric measurements and analysis of the products. At temperature below 100 °C, acetylene is adsorbed almost without dissociation and forms at least two different types of thermally stable adsorption complexes. Acetylene adsorbed at 200 °C is partly decomposed, especially in the low coverage region. Besides the above mentioned effects, the template effect of adsorbed acetylene was studied in the temperature range from -80° to 25 °C. It has been shown that this effect is a typical phenomenon of the palladium-acetylene system which is not due to surface impurities.

Ground-state switching characteristics in vertically-coupled InGaN/GaN quantum dots

2013 ◽  
Vol 63 (11) ◽  
pp. 2269-2272 ◽  
Author(s):  
Seoung-Hwan Park ◽  
Woo-Pyo Hong ◽  
Jong-Jae Kim
Keyword(s):  
Quantum Dots ◽  
Ground State ◽  
State Switching ◽  
Switching Characteristics

Thermoelectric Power in Quantum Confined Bismuth Under Classically Large Magnetic Field

1990 ◽  
Vol 216 ◽  
Author(s):  
Kamakhya P. Ghatak ◽  
S. N. Biswas
Keyword(s):  
Magnetic Field ◽  
Quantum Dots ◽  
Quantum Well ◽  
Film Thickness ◽  
Quantum Wells ◽  
Thermoelectric Power ◽  
Large Magnetic Field ◽  
Quantum Well Wires ◽  
Electron Dispersion ◽  
Theoretical Results

ABSTRACTIn this paper we studied the thermoelectric power under classically large magnetic field (TPM) in quantum wells (QWs), quantum well wires (QWWS) and quantum dots (QDs) of Bi by formulating the respective electron dispersion laws. The TPM increases with increasing film thickness in an oscillatory manner in all the cases. The TPM in QD is greatest and the least for quantum wells respectively. The theoretical results are in agreement with the experimental observations as reported elsewhere.

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