نتایج جستجو برای: quantum dots and rings

تعداد نتایج: 16919532  

Journal: :Journal of microscopy 2008
Y Williams S Byrne M Bashir A Davies A Whelan Y Gun'ko D Kelleher Y Volkov

Semiconductor nanoparticles or quantum dots are being increasingly utilized as fluorescent probes in cell biology both in live and fixed cell assays. Quantum dots possess an immense potential for use in multiplexing assays that can be run on high content screening analysers. Depending on the nature of the biological target under investigation, experiments are frequently required on cells retain...

2013
P. Tighineanu R. Daveau E. H. Lee J. D. Song S. Stobbe P. Lodahl

We investigate the optical emission and decay dynamics of excitons confined in large strain-free GaAs quantum dots grown by droplet epitaxy. From time-resolved measurements combined with a theoretical model we show that droplet-epitaxy quantum dots have a quantum efficiency of about 75% and an oscillator strength between 8 and 10. The quantum dots are found to be fully described by a model for ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تهران - دانشکده علوم 1380

هدف این پایان نامه تعیین تعداد مولدهای مینیمال ایده آلها در یک حلقه (جابجایی، یکدار، موضعی و نوتری) است، هر چند تعیین دقیق تعداد مولدها در حالتهایی خاص امکان پذیر است اما در حالتهای کلی روش های موجود بدست آوردن کرانهای مختلف برای تعداد مولدها است. مرجع اصلی این پایانامه ‏‎[1]‎‏ می باشد، به علاوه از نتایج جدیدی که در مرجع ‏‎‏‎[2]‎‏ نیز آمده استفاده کرده ایم. ‏‎[1]. j. sally. numbers of generator...

In this research, zinc oxide quantum dots and graphene nanocomposites were synthesized via two different methods; In the first (direct) method, ZnO-graphene Nanocomposites were made mixing the synthesized zinc oxide and graphene. In the second (indirect) method, zinc nitrate, graphene, and sodium hydroxide were used to made ZnO-graphene Nanocomposites. XRD, FTIR and Raman spectroscopy analyses ...

2004
Vladimir A. Fonoberov Alexander A. Balandin

We investigate theoretically and compare optical properties of wurtzite and zinc-blende GaN/AlN quantum dots with heights from 1.5 to 4.5 nm. The quantum dot size corresponds to the strong quantum confinement regime. It has been established that the built-in piezoelectric field at the GaN/AlN interface governs optical properties of wurtzite quantum dots while having a small effect on zinc-blend...

Journal: :Biosensors & bioelectronics 2010
Mark H Griep Karl A Walczak Eric M Winder Donald R Lueking Craig R Friedrich

Nanoscale sensing arrays utilizing the unique properties of the optical protein bacteriorhodopsin and colloidal semiconductor quantum dots are being developed for toxin detection applications. This paper describes an innovative method to activate bacteriorhodopsin-based electrodes with the optical output of quantum dots, producing an enhanced electrical response from the protein. Results show t...

2001
D. V. Regelman E. Dekel D. Gershoni E. Ehrenfreund W. V. Schoenfeld P. M. Petroff

We study optically single self-assembled quantum dots embedded within the wide quantum well of a mixed type quantum structure. We compare the steady state and pulsed photoluminescence spectra of these dots to those of previously studied " regular " dots. We unambiguously identify experimentally emission from various discrete charge state of the dots. We provide means for optically tune the char...

In this study the third order nonlinear susceptibilities are theoreticallycalculated for an electron confined in an isolated PbS/ CdSe/ CdS spherical core-shellshellquantum dots. Our calculation is associated with intersubband transitions in theconduction band. We used the effective mass approximation in this study which is asimple and straightforward study of the third-order optical nonlineari...

1998
K. Richter B. Mehlig

– We employ orbital magnetic response functions as a tool to investigate fluxdependent spectral correlations of chaotic quantum dots in the ballistic regime. We compare for the first time results for the persistent current and susceptibility from a semiclassical theory (without adjustable parameters) with accurate quantum-mechanical calculations for the case of an ensemble of chaotic rings thre...

2011
Roman Generalov Simona Kavaliauskiene Sara Westrøm Wei Chen Solveig Kristensen Petras Juzenas

Quantum dots have emerged with great promise for biological applications as fluorescent markers for immunostaining, labels for intracellular trafficking, and photosensitizers for photodynamic therapy. However, upon entry into a cell, quantum dots are trapped and their fluorescence is quenched in endocytic vesicles such as endosomes and lysosomes. In this study, the photophysical properties of q...

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