نتایج جستجو برای: coreshell shell quantum dot

تعداد نتایج: 357985  

2008
Joachim Kalden Kathrin Sebald Jürgen Gutowski Christian Tessarek Timo Aschenbrenner Stephan Figge Detlef Hommel

We present investigations of the optical properties of stacked InGaN quantum dot layers and demonstrate their advantage over single quantum dot layer structures. Measurements were performed on structures containing a single layer with quantum dots or threefold stacked quantum dot layers, respectively. A superlinear increase of the quantum dot related photoluminescence is detected with increasin...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه قم - دانشکده علوم پایه 1388

چکیده آزمایشها نشان می دهند، تغییر ویژگی های اپتیکی نقاط کوانتومی با کنترل شکل و اندازه آنها امکان پذیر است و کاهش تقارن فضایی، فیزیک جالبی را در این سیستم های کوانتوم مکانیکی ایجاد می- کند. تاثیر غیر کروی شدن، بصورت افزایش پهنای گذار های اپتیکی در نقاط کوانتومی مشهود است. در این پایان نامه با در نظر گرفتن اپتیک نقاط کوانتومی، پس از معرفی ویژگی ها، روش های تولید و کاربردهای نقاط کوانتومی، طی...

2018
Xiang-Bin Su Ying Ding Ben Ma Ke-Lu Zhang Ze-Sheng Chen Jing-Lun Li Xiao-Ran Cui Ying-Qiang Xu Hai-Qiao Ni Zhi-Chuan Niu

The device characteristics of semiconductor quantum dot lasers have been improved with progress in active layer structures. Self-assembly formed InAs quantum dots grown on GaAs had been intensively promoted in order to achieve quantum dot lasers with superior device performances. In the process of growing high-density InAs/GaAs quantum dots, bimodal size occurs due to large mismatch and other f...

2000
Constantine Yannouleas Uzi Landman

Interelectron interactions and correlations in quantum dots can lead to spontaneous symmetry breaking of the self-consistent mean field, resulting in the formation of Wigner molecules. With the use of spin-and-space unrestricted Hartree-Fock ~sS-UHF! calculations, such symmetry breaking is discussed for field-free conditions, as well as under the influence of an external magnetic field. Using a...

1997
J. Blaschke M. Brack

We present a semiclassical description of the level density of a two-dimensional circular quantum dot in a homogeneous magnetic field. We model the total potential (including electron-electron interaction) of the dot containing many electrons by a circular billiard, i.e., a hard-wall potential. Using the extended approach of the Gutzwiller theory developed by Creagh and Littlejohn, we derive an...

Journal: :Physical chemistry chemical physics : PCCP 2014
Lai-Hung Lai Loredana Protesescu Maksym V Kovalenko Maria A Loi

We report on the fabrication of PbS-CdS (core-shell) quantum dot (QD)-sensitized solar cells by direct adsorption of core-shell QDs on mesoporous TiO2 followed by 3-mercaptopropionic acid ligand exchange. PbS-CdS QD-sensitized solar cells show 4 times higher efficiency with respect to solar cells sensitized with PbS QDs. The significantly enhanced mean electron lifetime and electron diffusion l...

1997
J. Blaschke

We present a semiclassical description of the level density of a two-dimensional circular quantum dot in a homogeneous magnetic field. We model the total potential (including electron-electron interaction) of the dot containing many electrons by a circular billiard, i.e., a hard-wall potential. Using the extended approach of the Gutzwiller theory developed by Creagh and Littlejohn, we derive an...

2001
L P Kouwenhoven D G Austing S Tarucha

We review some electron transport experiments on few-electron, vertical quantum dot devices. The measurement of current versus source–drain voltage and gate voltage is used as a spectroscopic tool to investigate the energy characteristics of interacting electrons confined to a small region in a semiconducting material. Three energy scales are distinguished: the single-particle states, which are...

2016
Zerui Zheng Haining Ji Peng Yu Zhiming Wang

Quantum dot solar cells, as a promising candidate for the next generation solar cell technology, have received tremendous attention in the last 10 years. Some recent developments in epitaxy growth and device structures have opened up new avenues for practical quantum dot solar cells. Unfortunately, the performance of quantum dot solar cells is often plagued by marginal photon absorption. In thi...

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