Ultrafast energy relaxation in quantum dots through defect states: A lattice-relaxation approach

1997 ◽  
Vol 56 (16) ◽  
pp. 10423-10427 ◽  
Author(s):  
Xin-Qi Li ◽  
Yasuhiko Arakawa
Keyword(s):  
Quantum Dots ◽  
Lattice Relaxation ◽  
Energy Relaxation ◽  
Defect States

SURFACE LUMINESCENCE OF A2B6 SEMICONDUCTOR QUANTUM DOTS (REVIEW)

2021 ◽  
Vol 56 ◽  
pp. 27-38
Author(s):  
D. V. Korbutyak ◽  
Keyword(s):  
Quantum Dots ◽  
Surface Defect ◽  
Chemical Nature ◽  
Lattice Relaxation ◽  
Localized States ◽  
Exciton Luminescence ◽  
Defect States ◽  
Semiconductor Compounds ◽  
Surface Luminescence ◽  
Ab Initio Approach

Semiconductor zero-dimensional nanocrystals – quantum dots (QDs) – have been increasingly used in various fields of opto- and nanoelectronics in recent decades. This is because of the exciton nature of their luminescence, which can be controlled via the well known quantum-dimensional effect. At the same time, at small nanocrystall sizes, the influence of the surface on the optical and structural properties of nanocrystals increases significantly. The presence of broken bonds of surface atoms and point defects – vacancies and interstial atoms – can both weaken the exciton luminescence and create new effective channels of radiant luminescence. In some cases, these surface luminescence becomes dominant, leading to optical spectra broadening up to the quasi-white light. The nature of such localized states often remains unestablished due to the large number of the possible sorts of defects in both of QD and its surrounding. In contrast to exciton luminescence, which can be properly described within effective-mass approximations, the optical properties of defects relay on chemical nature of both defect itsself and its surrounding, what cannot be provided by “hydrogen-type coulomb defect” approximation. Moreover, charge state and related to this lattice relaxation must be taken into account, what requires an application of atomistic approach, such as Density functioal theory (DFT). Therefore, this review is devoted to the study of surface (defect) states and related luminescence, as well as the analysis of possible defects in nanocrystals of semiconductor compounds A2B6 (CdS, CdZnS, ZnS), responsible for luminescence processes, within ab initio approach. The review presents the results of the authors' and literature sources devoted to the study of the luminescent characteristics of ultra-small (<2 nm) QDs.

Polaron lifetime and energy relaxation in semiconductor quantum dots

2000 ◽  
Vol 62 (8) ◽  
pp. R4809-R4812 ◽  
Author(s):  
O. Verzelen ◽  
R. Ferreira ◽  
G. Bastard
Keyword(s):  
Quantum Dots ◽  
Energy Relaxation ◽  
Semiconductor Quantum Dots

RF-MBE Growth of InN Dots on N-polar GaN Grown on Vicinal c-plane Sapphire

2004 ◽  
Vol 831 ◽  
Author(s):  
Naoki Hashimoto ◽  
Naohiro Kikukawa ◽  
Song-Bek Che ◽  
Yoshihiro Ishitani ◽  
Akihiko Yoshikawa
Keyword(s):  
Quantum Dots ◽  
Molecular Beam Epitaxy ◽  
Radio Frequency ◽  
Growth Mechanism ◽  
Molecular Beam ◽  
Lattice Relaxation ◽  
Radio Frequency Plasma ◽  
Mbe Growth ◽  
Frequency Plasma ◽  
Nominal Coverage

ABSTRACTWe have grown InN quantum dots (QDs) on nitrogen-polarity (N-polarity) GaN under-layer by the radio-frequency plasma-assisted molecular beam epitaxy (RF-MBE), and systematically investigated growth mechanism of the InN dots. The InN QDs with the N-polarity could be grown at about 500°C, which was much higher than that of previous reports on InN dots grown by MBE. When the nominal coverage of InN became more than 1 mono-layer (ML), lattice relaxation of InN occurred and high density InN dots were uniformly formed. These results indicated that InN dots were formed by Stranski-Krastanov (S-K) growth mode. For the InN deposition above about 8ML, InN dots tended to coalesce and resulted in remarakable decrease of the dots density.

scholarly journals Mechanisms of fluorescence decays of colloidal CdSe–CdS/ZnS quantum dots unraveled by time-resolved fluorescence measurement

2015 ◽  
Vol 17 (41) ◽  
pp. 27588-27595 ◽  
Author(s):  
Hao Xu ◽  
Volodymyr Chmyrov ◽  
Jerker Widengren ◽  
Hjalmar Brismar ◽  
Ying Fu
Keyword(s):  
Quantum Dots ◽  
Radiative Recombination ◽  
Energy Relaxation ◽  
Fluorescence Decay ◽  
Fluorescence Measurement ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Decay Spectrum

The fluorescence decay spectrum of colloidal CdSe-based quantum dots is characterized by energy relaxation and radiative recombination of photoexcited excitons.

Energy relaxation by multiphonon processes in InAs/GaAs quantum dots

1997 ◽  
Vol 56 (16) ◽  
pp. 10435-10445 ◽  
Author(s):  
R. Heitz ◽  
M. Veit ◽  
N. N. Ledentsov ◽  
A. Hoffmann ◽  
D. Bimberg ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Energy Relaxation

Giant Nanocrystal Quantum Dots: Stable Down-Conversion Phosphors that Exploit a Large Stokes Shift and Efficient Shell-to-Core Energy Relaxation

Nano Letters ◽  
2012 ◽  
Vol 12 (6) ◽  
pp. 3031-3037 ◽  
Author(s):  
Janardan Kundu ◽  
Yagnaseni Ghosh ◽  
Allison M. Dennis ◽  
Han Htoon ◽  
Jennifer A. Hollingsworth
Keyword(s):  
Quantum Dots ◽  
Stokes Shift ◽  
Energy Relaxation ◽  
Large Stokes Shift ◽  
Core Energy ◽  
Nanocrystal Quantum Dots ◽  
Down Conversion
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