نتایج جستجو برای: semiconductor quantum dot

تعداد نتایج: 361260  

2008
Guillaume Tarel Vincenzo Savona

We model the emission spectrum of a quantum dot embedded in a (e.g. photonic crystal) nanocavity, using a semi-classical approach to describe the matter-field interaction. We start from the simple model of a quantum dot as a two-level system, and recover the result expected from cavity quantum electrodynamics. Then, we study the influence of electron-acoustic-phonons interaction. We show that t...

1997
Todd D. Krauss Frank W. Wise

Coherent acoustic phonons in PbS quantum dots are observed using femtosecond optical techniques. This is the first observation of coherent acoustic phonons in a semiconductor quantum dot; the phonons are generated through the deformation-potential coupling to the quantum-dot exciton. The acoustic modes are weakly damped, and we also find extremely weak coupling (S , 0.01) to the optical modes. ...

Journal: :Physical review letters 2002
Matthew Pelton Charles Santori Jelena Vucković Bingyang Zhang Glenn S Solomon Jocelyn Plant Yoshihisa Yamamoto

We have demonstrated efficient production of triggered single photons by coupling a single semiconductor quantum dot to a three-dimensionally confined optical mode in a micropost microcavity. The efficiency of emitting single photons into a single-mode traveling wave is approximately 38%, which is nearly 2 orders of magnitude higher than for a quantum dot in bulk semiconductor material. At the ...

2008
Anna Grodecka Paweł Machnikowski Jens Förstner

Phonon-assisted singlet-singlet relaxation in semiconductor quantum dot molecules is studied theoretically. Laterally coupled quantum dot structures doped with two electrons are considered. We take into account interaction with acoustic phonon modes via deformation potential and piezoelectric coupling. We show that piezoelectric mechanism for the considered system is of great importance and for...

ژورنال: فیزیک کاربردی 2019

ضخامت لایۀ­ نقاط کوانتومی و نیمه­رسانای شفاف با شکاف بزرگ، میزان ناخالصی لایۀ نقاط کوانتومیو نوع فلز آند از جمله عوامل تأثیرگذار بر بازدهِ سلول­های خورشیدی نقطۀ کوانتومی ناهمجنس (HQDSC) می­باشند. در این مقاله با استفاده از نرم­افزار کامسول نسخه 4/5، ابتدا سلولی شامل یک لایه از نقاط کوانتومی سولفید سرب (PbS) پوشیده از لیگاندهای کوتاه و یک لایه نیمه­رسانای اکسید روی (ZnO) و آندی از جنس طلا شبیه­سا...

2016
H. Snijders J. A. Frey J. Norman M. P. Bakker E. C. Langman A. Gossard J. E. Bowers M. P. van Exter D. Bouwmeester W. Löffler

Single photon nonlinearities based on a semiconductor quantum dot in an optical microcavity are a promising candidate for integrated optical quantum information processing nodes. In practice, however, the finite quantum dot lifetime and cavity-quantum dot coupling lead to reduced fidelity. Here we show that, with a nearly polarization degenerate microcavity in the weak coupling regime, polariza...

2006
Wei Zhang Tianming Dong Alexander O. Govorov

We show that a double quantum-dot system made of diluted magnetic semiconductor behaves unlike usual molecules. In a semiconductor double quantum dot or in a diatomic molecule, the ground state of a single carrier is described by a symmetric orbital. In a magnetic material molecule, new ground states with broken symmetry can appear due the competition between the tunnelling and magnetic polaron...

Journal: :Physical review letters 2009
Edward B Flagg John W Robertson Sébastien Founta Wenquan Ma Min Xiao Gregory J Salamo Chih-Kang Shih

Using resonance fluorescence, we investigate how acoustic phonons mediate couplings between multiple electronic levels in a semiconductor quantum dot. We show the first direct evidence of population up-conversion in a single quantum dot, which we attribute to absorption of single acoustic phonons. Moreover, through a rate equation analysis, we find that below 20 K such single-phonon mediated co...

Journal: :Nano letters 2006
Jean-Michel Caruge Jonathan E Halpert Vladimir Bulović Moungi G Bawendi

We demonstrate a hybrid inorganic/organic light-emitting device composed of a CdSe/ZnS core/shell semiconductor quantum-dot emissive layer sandwiched between p-type NiO and tris-(8-hydroxyquinoline) aluminum (Alq3), as hole and electron transporting layers, respectively. A maximum external electroluminescence quantum efficiency of 0.18% is achieved by tuning the resistivity of the NiO layer to ...

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