Search query: Quantum dot lifetime

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abstract: We investigate photoluminescence from individual "giant" CdSe/CdS core/thick shell quantum dots (gQDs) placed near an epitaxial Ag film with an atomically smooth surface. The key observation is that the lifetimes of the gQDs are drastically reduced and exhibit a remarkably narrow distribution compared to the gQDs deposited on a thermally deposited Ag film. The larger variations in gQDs' lifetimes on the thermally deposited Ag film arise from excitonic coupling to localized surface plasmons associated with nanoscale surface corrugations of different heights. A calculation is performed based on a simple model system of a QD coupled to a metallic nanosphere. The calculation shows that the QD lifetime initially shortens and reaches a saturated value with increasing radius of the metal nanoparticle (MNP) Because the epitaxial film can be treated as a sphere with an infinitely large radius, the calculation confirms and explains the different QD dynamics near the two types of Ag films as observed experimentally.
author_names: Thomas Hartsfield

Michael Gegg

Ping-Hsiang Su

Matthew R G Buck

Jennifer Ann Hollingsworth

Chih-Kang Shih

Marten Richter

Han Htoon

Xiaoqin Li
title: Semiconductor Quantum Dot Lifetime Near an Atomically Smooth Ag Film Exhibits a Narrow Distribution
year: 2016

abstract: All solution processed inverted quantum dot light emitting diodes (QLEDs) are promising candidates for lighting and display applications. While the external quantum efficiency of inverted devices is comparable to that of devices with normal structure, achieving both high efficiency and long lifetime in such inverted devices remains challenging. Herein, we report an all solution processed inverted green QLED capable of achieving a 96.42 cd A 1 current efficiency, a 25.04% external quantum efficiency, and a 4943.6 h half lifetime. This external quantum efficiency exceeds reported literature values, and the lifetime is over 19 times greater than those of previously reported all solution processed inverted QLEDs. Such excellent performance is attributed to the precisely controlled double ZnS shells of CdSeZnS/ZnS/ZnS quantum dots, which can effectively suppress Auger recombination and Forster resonance energy transfer, as well as decrease efficiency roll off at high driving currents. Overall, this study suggests that shell engineering of quantum dots may provide an effective means of accelerating the inverted QLEDs to meet requirements for practical display and lighting applications.
author_names: Zhiwen Yang

Qianqian Wu

Gongli Lin

Xiaochuan Zhou

Weijie Wu

Xuyong Yang

Jianhua Zhang

Li Wanwan
title: All solution processed inverted green quantum dot light emitting diodes with concurrent high efficiency and long lifetime
year: 2019

abstract: We investigate the impact of threading dislocation density on the reliability of 1.3 mm InAs quantum dot lasers epitaxially grown on Si. A reduction in the threading dislocation density from 2.8 x 108 cm 2 to 7.3 x 106 cm 2 has improved the laser lifetime by about five orders of magnitude when aged continuous wave near room temperature (35 degC) We have achieved extrapolated lifetimes (time to double initial threshold) more than 10 x 106 h. An accelerated laser aging test at an elevated temperature (60 degC) reveals that p modulation doped quantum dot lasers on Si retain superior reliability over unintentionally doped ones. These results suggest that epitaxially grown quantum dot lasers could be a viable approach to realize a reliable, scalable, and efficient light source on Si.
author_names: Daehwan Jung

Robert Herrick

Justin C Norman

Katherine Turnlund

Catherine Jan

Kaiyin Feng

Arthur C Gossard

John E Bowers
title: Impact of threading dislocation density on the lifetime of InAs quantum dot lasers on Si
year: 2018

abstract: Establishing a highly efficient photon emitter interface where the intrinsic linewidth broadening is limited solely by spontaneous emission is a key step in quantum optics. It opens a pathway to coherent light matter interaction for, e.g. the generation of highly indistinguishable photons, few photon optical nonlinearities, and photon emitter quantum gates. However, residual broadening mechanisms are ubiquitous and need to be combated. For solid state emitters charge and nuclear spin noise are of importance, and the influence of photonic nanostructures on the broadening has not been clarified. We present near lifetime limited linewidths for quantum dots embedded in nanophotonic waveguides through a resonant transmission experiment. It is found that the scattering of single photons from the quantum dot can be obtained with an extinction of 66 4% which is limited by the coupling of the quantum dot to the nanostructure rather than the linewidth broadening. This is obtained by embedding the quantum dot in an electrically contacted nanophotonic membrane. A clear pathway to obtaining even larger single photon extinction is laid out; i.e. the approach enables a fully deterministic and coherent photon emitter interface in the solid state that is operated at optical frequencies.
author_names: Henri Thyrrestrup

Gabija Kirsanske

Hanna Le Jeannic

Tommaso Pregnolato

Liang-Jun Zhai

Laust Raahauge

Leonardo Midolo

Nir Rotenberg

Alisa Javadi

Rudiger Schott

Andreas Dirk Wieck

Arne Ludwig

Matthias Christian Lobl

Immo Sollner

Richard John Warburton

Peter Lodahl
title: Quantum Optics with Near Lifetime Limited Quantum Dot Transitions in a Nanophotonic Waveguide.
venue: Nano letters
year: 2018

abstract: We investigate the magnetic field and temperature dependence of the single electron spin lifetime in silicon quantum dots and find a lifetime of 2.8 ms at a temperature of 1.1 K. We develop a model based on spin valley mixing and find that Johnson noise and two phonon processes limit relaxation at low and high temperature, respectively. We also investigate the effect of temperature on charge noise and find a linear dependence up to 4 K. These results contribute to the understanding of relaxation in silicon quantum dots and are promising for qubit operation at elevated temperatures.
author_names: L Petit

J M Boter

H G J Eenink

Gabriel Droulers

Marco Lorenzo Valerio Tagliaferri

R Li

David P Franke

K J Singh

James S Clarke

R N Schouten

Viatcheslav V Dobrovitski

Lieven M K Vandersypen

Menno Veldhorst
title: Spin Lifetime and Charge Noise in Hot Silicon Quantum Dot Qubits.
venue: Physical review letters
year: 2018

abstract: High performance III V quantum dot lasers monolithically grown on Si substrates have been demonstrated as a promising solution to realize Si based laser sources with very low threshold current density, high output power, and long lifetime, even with relatively high density of defects due to the material dissimilarities between III Vs and Si. On the other hand, although conventional III V quantum well lasers grown on Si have been demonstrated after great efforts worldwide for more than 40 years, their practicality is still a great challenge because of their very high threshold current density and very short lifetime. However, the physical mechanisms behind the superior performance of silicon based III V quantum dot lasers remain unclear. In this paper, we directly compare the performance of a quantum well and a quantum dot laser monolithically grown on on axis Si (001) substrates, both experimentally and theoretically, under the impact of the same density of threading dislocations. A quantum dot laser grown on a Si substrate with a high operating temperature (105 degC) has been demonstrated with a low threshold current density of 173 A/cm2 and a high single facet output power >100 mW at room temperature, while there is no lasing operation for the quantum well device at room temperature even at high injection levels. By using a rate equation travelling wave model, the quantum dot laser's superior performance compared with its quantum well based counterpart on Si is theoretically explained in terms of the unique properties of quantum dots, i.e. efficient carrier capture and high thermal energy barriers preventing the carriers from migrating into defect states.
author_names: Zizhuo Liu

Mickael Martin

Thierry Baron

Siming Chen

Alwyn J Seeds

Richard Vincent Penty

Ian H White

Huiyun Liu

Constanze Hantschmann

Mingchu Tang

Ying Lu

Jae-Seong Park

Mengya Liao

Shujie Pan

Ana M Sanchez

Richard Beanland
title: Origin of Defect Tolerance in InAs/GaAs Quantum Dot Lasers Grown on Silicon
venue: Journal of Lightwave Technology
year: 2020

abstract: Quantum dots are increasingly used in displays to achieve high color gamut at high efficiency. This paper describes the impact of quantum dot lifetime on long term display performance and the methods used for predicting in device lifetime from accelerated aging results. Test methods are described which give confidence in aging predictions.
author_names: James Thielen

Dave Lamb

Abby Lemon

Josh Tibbits

John F Van Derlofske

Eric W Nelson
title: 27 2: Invited Paper: Correlation of Accelerated Aging to In Device Lifetime of Quantum Dot Enhancement Film
year: 2016

abstract: Semiconductor nanocrystals or quantum dots (QDs) should act as excellent Forster resonance energy transfer (FRET) acceptors due to their large absorption cross section, tunable emission, and high quantum yields. Engaging this type of FRET can be complicated due to direct excitation of the QD acceptor along with its longer excited state lifetime. Many cases of QDs acting as energy transfer acceptors are within time gated FRET from long lifetime lanthanides, which allow the QDs to decay before observing FRET. Efficient QD sensitization requires the lanthanide to be in close proximity to the QD. To overcome the lifetime mismatch issues and limited transfer range, we utilized a Cy3 dye to bridge the energy transfer from an extremely long lived terbium emitter to the QD. We demonstrated that short lifetime dyes can be used as energy transfer relays between extended lifetime components and in this way increased the distance of terbium QD FRET to ~14 nm.
author_names: Sebastian A Diaz

Guillermo Lasarte Aragones

Susan Buckhout-White

Xue Qiu

Eunkeu Oh

Kimihiro Susumu

Joseph S Melinger

Alan L Huston

Niko Hildebrandt

Igor L Medintz
title: Bridging Lanthanide to Quantum Dot Energy Transfer with a Short Lifetime Organic Dye.
venue: The journal of physical chemistry letters
year: 2017

abstract: To make quantum dot sensitized solar cells (QDSSCs) competitive, we investigated the effect of Ni(2+ ion incorporation into a CdS layer to create long lived charge carriers and reduce the electron hole recombination. The Ni(2+ doped CdS (simplified as CdNiS) QD layer was introduced to a TiO2 surface via the simple successive ionic layer adsorption and reaction (SILAR) method in order to introduce intermediate energy levels in the QDs. The effects of different Ni(2+ concentrations (5, 10, 15, and 20 mM) on the physical, chemical, and photovoltaic properties of the QDSSCs were investigated. The Ni(2+ dopant improves the light absorption of the device, accelerates the electron injection kinetics, and reduces the charge recombination, which results in improved charge transfer and collection. The 15% CdNiS cell exhibits the best photovoltaic performance with a power conversion efficiency (e) of 3.11% (JSC 8.91 mA cm( 2) VOC 0.643 V, FF 0.543) under one full sun illumination (AM 1.5 G) These results are among the best achieved for CdS based QDSSCs. Electrochemical impedance spectroscopy (EIS) and open circuit voltage decay (OCVD) measurements confirm that the Ni(2+ dopant can suppress charge recombination, prolong the electron lifetime, and improve the power conversion efficiency of the cells.
author_names: Chandu V V Muralee Gopi

Mallineni Venkata-Haritha

Hyunwoong Seo

Saurabh Singh

Soo-Kyoung Kim

Masaharu Shiratani

Hee-Jee Kim
title: Improving the performance of quantum dot sensitized solar cells through CdNiS quantum dots with reduced recombination and enhanced electron lifetime.
venue: Dalton transactions
year: 2016

abstract: The low efficiency and fast degradation of devices from ink jet printing process hinders the application of quantum dot light emitting diodes on next generation displays. Passivating the trap states caused by both anion and cation under coordinated sites on the quantum dot surface with proper ligands for ink jet printing processing reminds a problem. Here we show, by adapting the idea of dual ionic passivation of quantum dots, ink jet printed quantum dot light emitting diodes with an external quantum efficiency over 16% and half lifetime of more than 1,721,000 hours were reported for the first time. The liquid phase exchange of ligands fulfills the requirements of ink jet printing processing for possible mass production. And the performance from ink jet printed quantum dot light emitting diodes truly opens the gate of quantum dot light emitting diode application for industry. Designing efficient and scalable quantum dot LEDs meeting industrial requirements remains a challenge. Here, the authors, by leveraging the liquid phase exchange of d MX 2 ligands, present printed quantum dot LEDs with external quantum efficiency over 16% and half lifetime of more than 1,721,000 hours.
author_names: Chaoyu Xiang

Longjia Wu

Zizhe Lu

Menglin Li

Yanwei Wen

Yixing Yang

Wenyong Liu

Tong-Yi Zhang

Weiran Cao

Sai-Wing Tsang

Bin Shan

Xiaolin Yan

Lei Qian
title: High efficiency and stability of ink jet printed quantum dot light emitting diodes
venue: Nature Communications
year: 2020