scholarly journals Фотодинамика переноса возбуждения носителями заряда в гибридной наносистеме InP/InAsP/InP

2021 ◽  
Vol 129 (7) ◽  
pp. 948
Author(s):  
А.С. Рубан ◽  
В.В. Данилов
Keyword(s):  
Quantum Dots ◽  
Band Gap ◽  
Transfer Process ◽  
Radiative Recombination ◽  
Reverse Transfer ◽  
Semiconductor Nanostructure ◽  
Kinetics Of ◽  
Inp Surface

The results of processing the luminescence attenuation kinetics of an InP/InAsP/InP hybrid semiconductor nanostructure with deposited colloidal layers of CdSe/ZnS quantum dots (QD) under excitation at wavelengths of 532 and 633 nm and temperatures of 80 and 300 K. Such a nanostructure is characterized by a significant increase in the duration and intensity of the luminescence of the INASP nanostructure. The mechanism of increasing the luminescence duration is presumably associated with the interaction of the QD CdSe/ZnS-TORO colloid with the InP surface, which leads to the formation of new hybrid states in the band gap that are energetically close to the radiating state and are able to capture electrons, which in turn is compensated by the increasing role of the electron reverse transfer process, which leads to an increase in the duration of radiative recombination.

scholarly journals Influence of TOPO and TOPO-CdSe/ZnS Quantum Dots on Luminescence Photodynamics of InP/InAsP/InPHeterostructure Nanowires

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 640
Author(s):  
Artem I. Khrebtov ◽  
Vladimir V. Danilov ◽  
Anastasia S. Kulagina ◽  
Rodion R. Reznik ◽  
Ivan D. Skurlov ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Excited States ◽  
Molecular Beam ◽  
Surface Passivation ◽  
Low Energy ◽  
Trioctylphosphine Oxide ◽  
Reverse Transfer ◽  
Semiconductor Heterostructure ◽  
Ligand Type

The passivation influence by ligands coverage with trioctylphosphine oxide (TOPO) and TOPO including colloidal CdSe/ZnS quantum dots (QDs) on optical properties of the semiconductor heterostructure, namely an array of InP nanowires (NWs) with InAsP nanoinsertion grown by Au-assisted molecular beam epitaxy on Si (111) substrates, was investigated. A significant dependence of the photoluminescence (PL) dynamics of the InAsP insertions on the ligand type was shown, which was associated with the changes in the excitation translation channels in the heterostructure. This change was caused by a different interaction of the ligand shells with the surface of InP NWs, which led to the formation of different interfacial low-energy states at the NW-ligand boundary, such as surface-localized antibonding orbitals and hybridized states that were energetically close to the radiating state and participate in the transfer of excitation. It was shown that the quenching of excited states associated with the capture of excitation to interfacial low-energy traps was compensated by the increasing role of the “reverse transfer” mechanism. As a result, the effectiveness of TOPO-CdSe/ZnS QDs as a novel surface passivation coating was demonstrated.

Optical and Electron Correlation Effects in Silicon Quantum Dots

2005 ◽  
Vol 23 ◽  
pp. 129-132 ◽  
Author(s):  
S.K. Ghoshal ◽  
K.P. Jain ◽  
R. Elliott
Keyword(s):  
Quantum Dots ◽  
Band Gap ◽  
Surface Passivation ◽  
Surface States ◽  
Hydrogen Atoms ◽  
Basis Expansion ◽  
Electron Correlation Effects ◽  
Homo Lumo ◽  
Pseudo Potential

We study (through computer simulation) the variation of the band gap as a function of sizes and shapes of small Silicon (Si) dots using pseudo-potential approach. We have used empirical pseudo-potential Hamiltonian and a plane wave basis expansion and a basic tetrahedral structure. It is found that the gap decreases for increasing dot size. Furthermore, the band gap increases as much as 0.13eV on passivation the surface of the dot with hydrogen. So both quantum confinement and surface passivation determine the optical and electronic properties of Si quantum dots. Visible luminescence is probably due to radiative recombination of electrons and holes in the quantum confined nanostructures. The effect of passivation of the surface dangling bonds by hydrogen atoms and the role of surface states on the gap energy as well as on the HOMO-LUMO states has also been examined. We have investigated the entire energy spectrum starting from the very low lying ground state to the very high lying excited states for silicon dots having 5, 18, 17 and 18 atoms. The results for the size dependence of the HOMO-LUMO gap and the wave functions for the bonding-antibonding states are presented and the importance of the confinement and the role of hydrogen passivation on the confinement are also discussed.

scholarly journals Фотодинамика люминесценции гибридных наноструктур InP/InAsP/InP ННК, пассивированных слоем ТОРО-CdSe/ZnS КТ

2020 ◽  
Vol 54 (9) ◽  
pp. 952
Author(s):  
А.И. Хребтов ◽  
А.С. Кулагина ◽  
В.В. Данилов ◽  
Е.С. Громова ◽  
И.Д. Скурлов ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Radiative Recombination ◽  
Near Infrared ◽  
Infrared Region ◽  
Trioctylphosphine Oxide ◽  
Type Ii ◽  
Semiconductor Nanostructure ◽  
Interfacial Processes ◽  
Near Infrared Region ◽  
Spectrally Resolved

The results of studies of the photodynamics of the excited state decay of a hybrid semiconductor nanostructure, which is an array of InP nanowires with InAsP nanoinsertions passivated with a layer of TOPO (trioctylphosphine oxide) containing colloidal CdSe/ZnS quantum dots, are presented. Time- and spectrally resolved measurement of photoluminescence InAsP nanoinsertions in the near infrared region at temperatures of 80 K and 293 K were made. The presence of a quasi-Langmuir layer of TOPO-CdSe/ZnS quantum dots on the surface of InP/InAsP/InP nanowires leads to an increase in the duration of radiative recombination and its dependence on temperature. It was found that the synthesized structure has a type-II heterojunction at the interface between the InAsP nanoinsertion and the InP volume. The influence of interfacial processes on increasing the duration of radiative recombination is discussed.

Radiative recombination in photoexcited quantum dots up to room temperature: The role of fine-structure effects

2010 ◽  
Vol 81 (24) ◽  
Author(s):  
T. Kümmell ◽  
S. V. Zaitsev ◽  
A. Gust ◽  
C. Kruse ◽  
D. Hommel ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Fine Structure ◽  
Radiative Recombination ◽  
Room Temperature

scholarly journals Recombination kinetics of InAs quantum dots: Role of thermalization in dark states

2006 ◽  
Vol 73 (8) ◽  
Author(s):  
M. Gurioli ◽  
A. Vinattieri ◽  
M. Zamfirescu ◽  
M. Colocci ◽  
S. Sanguinetti ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Inas Quantum Dots ◽  
Kinetics Of ◽  
Recombination Kinetics
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