- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Cascade Structured ZnO/TiO2/CdS quantum dot sensitized solar cell
摘要： Cascade structure of ZnO/TiO2/CdS quantum dot sensitized solar cell (QDSSC) using precursor solutions of CdS quantum dots having different concentrations such as 0.1 M, 0.2 M, 0.5 M and 0.8 M were synthesized on fluorine doped tin oxide (FTO) substrate, using the successive ionic layer absorption and reaction (SILAR) method. A polysulfide electrolyte was used as a redox mediator. The combination of ZnO/TiO2 used as a photoanode gives the best results and changes the mechanism of the QDSSC. The conventional Pt counter electrode was replaced by a low cost CuS counter electrode. Morphological and structural characterizations were carried out by field-emission scanning electron microscope (FESEM) & X-ray diffractometer, respectively. The optical characterizations were carried out by using ultraviolet–visible (UV–Vis) spectroscopy. Degree of porosity of prepared quantum dot (QD) sensitizers on TiO2/ZnO surface of different precursor concentrations 48.90%, 45.90%, 44.20% and 42.41% were observed. J-V characteristics and the performance of the prototype solar cell devices were evaluated by using a solar simulator, under illumination with an AM 1.5G spectrum having light intensity of 100 mWcm?2. The highest efficiency was obtained 2.44% at 0.1 M concentration and the lowest was 0.52% at 0.8 M concentration.
关键词： Quantum dot sensitized solar cell,ZnO/TiO2/CdS,Counter electrode
更新于2025-09-23 15:21:01
-
New Majority Gate Based Parallel BCD Adder Designs for Quantum-dot Cellular Automata
摘要： In this paper, we ?rst theoretically re-de?ned output decimal carry in terms of majority gates and proposed a carry lookahead structure for calculating all the intermediate output carries. We have used this method for designing the multi-digit decimal adders. Theoretically, our best n-digit decimal adder design reduces the delay and area-delay product (ADP) by 50% compared with previous designs. We have implemented our designs using QCADesigner tool. The proposed QCADesigner based 8-digit PBA-BCD adder achieves over 38% less delay compared with the best existing designs.
关键词： carry lookahead,Majority gate,quantum-dot cellular automata,parallel BCD adder
更新于2025-09-23 15:21:01
-
Comparative Study of Time-Resolved Fluorescent Nanobeads, Quantum Dot Nanobeads and Quantum Dots as Labels in Fluorescence Immunochromatography for Detection of Aflatoxin B1 in Grains
摘要： Label selection is an essential procedure for improving the sensitivity of fluorescence immunochromatography assays (FICAs). Under optimum conditions, time-resolved fluorescent nanobeads (TRFN), quantum dots nanobeads (QB) and quantum dots (QD)-based immunochromatography assays (TRFN-FICA, QB-FICA and QD-FICA) were systematically and comprehensively compared for the quantitative detection of aflatoxin B1 (AFB1) in six grains (corn, soybeans, sorghum, wheat, rice and oat). All three FICAs can be applied as rapid, cost-effective and convenient qualitative tools for onsite screening of AFB1; TRFN-FICA exhibits the best performance with the least immune reagent consumption, shortest immunoassay duration and lowest limit of detection (LOD). The LODs for TRFN-FICA, QB-FICA and QD-FICA are 0.04, 0.30 and 0.80 μg kg?1 in six grains, respectively. Recoveries range from 83.64% to 125.61% at fortified concentrations of LOD, 2LOD and 4LOD, with the coefficient of variation less than 10.0%. Analysis of 60 field grain samples by three FICAs is in accordance with that of LC-MS/MS, and TRFN-FICA obtained the best fit. In conclusion, TRFN-FICA is more suitable for quantitative detection of AFB1 in grains when the above factors are taken into consideration.
关键词： aflatoxin B1,immunochromatography,time-resolved fluorescent nanobeads,quantum dot nanobeads,quantum dot
更新于2025-09-23 15:19:57
-
Entanglement teleportation with photons from quantum dots: towards a solid-state based quantum network
摘要： Semiconductor quantum dots are currently emerging as one of the most promising sources of non-classical light on which to base future quantum networks. They can generate single photons as well as pairs of entangled photons with unprecedented brightness, indistinguishability, and degree of entanglement. These features have very recently opened up the possibility to perform advanced quantum optics protocols that were previously inaccessible to single quantum emitters. In this work, we report on two experiments that use the non-local properties of entanglement to teleport quantum states: three-photon state teleportation and four-photon entanglement teleportation. We discuss all the experimental results in light of a theoretical model that we develop to account for the non-idealities of the quantum source. The excellent agreement between theory and experiment enables a deep understanding of how each parameter of the source affects the teleportation fidelities and it pinpoints the requirements needed to overcome the classical limits. Finally, our model suggests how to further improve quantum-dot entangled-photon sources for practical quantum networks.
关键词： quantum teleportation,entanglement swapping,quantum optics,semiconductor physics,quantum entanglement,quantum dot
更新于2025-09-23 15:19:57
-
All-photonic quantum teleportation using on-demand solid-state quantum emitters
摘要： All-optical quantum teleportation lies at the heart of quantum communication science and technology. This quantum phenomenon is built up around the nonlocal properties of entangled states of light that, in the perspective of real-life applications, should be encoded on photon pairs generated on demand. Despite recent advances, however, the exploitation of deterministic quantum light sources in push-button quantum teleportation schemes remains a major open challenge. Here, we perform an important step toward this goal and show that photon pairs generated on demand by a GaAs quantum dot can be used to implement a teleportation protocol whose fidelity violates the classical limit (by more than 5 SDs) for arbitrary input states. Moreover, we develop a theoretical framework that matches the experimental observations and that defines the degree of entanglement and indistinguishability needed to overcome the classical limit independently of the input state. Our results emphasize that on-demand solid-state quantum emitters are one of the most promising candidates to realize deterministic quantum teleportation in practical quantum networks.
关键词： GaAs quantum dot,entangled photon pairs,quantum emitters,quantum teleportation,quantum communication
更新于2025-09-23 15:19:57
-
Carrier transport and recombination dynamics of InAs/GaAs sub-monolayer quantum dot near infrared photodetector
摘要： Here, we present a relative study of tunnel-induced photocarrier escape processes in a laterally coupled InAs sub-monolayer quantum dot-based photodetector (SML QD-PD) as a function of fractional coverage from 0.4 ML to 0.8 ML. Both by simulation and experiment, we have quantitatively described the temperature dependent interband photoresponse spectrally tuned in the near infrared region (835 nm–890 nm) on the basis of mutual competition between the interband carrier recombination and interdot tunneling lifetime with varying SML coverage. The progressively increasing recombination lifetime and decreasing interdot tunneling lifetime with increasing SML coverage has attributed to a faster photoresponse and greater responsivity. At higher coverage fraction, tunnel induced fast speed photocarrier transit through lateral array of SML QDs has been found to be capable of offering a faster temporal response (100 μs) with faithful reproducibility up to higher frequencies (1.3 KHz). Here, we report a powerful strategy to simultaneously tune responsivity, speed of time response and detectivity by externally controlling the SML coverage. This time response is measured to be nine times faster than a conventional SK QD photodetector. With increased coverage, inhibition of dark current due to trapping of injected charge carriers up to higher temperatures have resulted in high sustainable photodetectivity of 8 × 1011 cm Hz1/2 w?1 at ~250 K that offers near room temperature photodetection.
关键词： photoconductive gain,quantum dot photodetector,inter-dot tunneling,submonolayer coverage,near-infrared photoresponse,recombination dynamics,temporal photoresponse
更新于2025-09-23 15:19:57
-
Implementations of more general solid-state (SWAP)${}^{1/m}$ and controlled-(swap)${}^{1/m}$ gates
摘要： Universal quantum gates are the core elements in quantum information processing. We design two schemes to realize more general (SWAP)1/m and controlled-(swap)1/m gates (for integer m 1? ) by directing ?ying single photons to solid-state quantum dots. The parameter m is easily controlled by adjusting two quarter-wave plates and one half-wave plate. Additional computational qubits are not required to construct the two gates. Evaluations of the gates indicate that our proposals are feasible with current experimental technology.
关键词： quantum computation,quantum logic gate,(SWAP)1/m,quantum dot,controlled-(swap)1/m
更新于2025-09-23 15:19:57
-
Reduction of charge impurities in a silicon metal-oxide-semiconductor quantum dot qubit device patterned with nano-imprint lithography
摘要： The silicon metal-oxide-semiconductor quantum dot architecture is a leading approach for the physical implementation of semiconductor quantum computing. One major challenge for scalable quantum dots is the presence of charge impurities. Electron-beam lithography (EBL), almost universally used to fabricate quantum dot devices, is known to create such defects at the Si/SiO2 interface. To eliminate the need for EBL, we have transferred the metal gate pattern of a quantum dot onto the silicon substrate using nano-imprint lithography. Critical features with 50 nm scale and separation can be dependably reproduced. By characterizing the bias-dependent charge transport through a quantum point contact barrier, the prevalence of impurities is found to be largely diminished in nano-imprinted devices when compared to similar electron-beam-written counterparts. High-quality charge transport and charge sensing of several quantum dots are obtained. Additionally, gate noise is measured with an average of 1.5 μeV Hz?1/2 equivalent to previous measurements made on devices fabricated with EBL, which suggests that the leading source of impurities produced by EBL are deep, ?xed charges. This work offers a path toward reliable quantum dot operation in MOS by improving fabrication techniques to reduce charge impurities.
关键词： silicon metal–insulator–semiconductor,nano-imprint lithography,quantum dot,qubit,quantum information
更新于2025-09-23 15:19:57
-
A single plasmon router based on the V-type three-level quantum dot sandwiched between two plasmonic waveguides
摘要： A single photon router with a desired high routing rate is of great importance for quantum networks. Recently, coupling between channeled plasmons and quantum emitters have been widely used to explore the routing feasibility in hybrid systems. As a capable alternative, we suggested a scheme of a single plasmon router using a V-type three-level quantum dot (QD) sandwiched between two plasmonic waveguides. We theoretically investigated the transmission and transfer rates of single plasmons in the complex system via the real-space approach. Our calculations show that the single plasmons from the incident route could be redirected by controlling such parameters as the intensity of the classical field, the detunings and the couplings between the QD and the plasmonic waveguides. Our proposed scheme could be used not only for the design of a single plasmon router but also for the design of quantum switches and quantum couplers in quantum photonic integrated circuits.
关键词： waveguide,single plasmon,quantum dot,quantum router
更新于2025-09-23 15:19:57
-
Theoretical investigation on the third order nonlinear optical susceptibility in CdS/ZnS/CdS/ZnS core/shell/well/shell quantum dots for optoelectronic applications
摘要： In this paper, a detailed study on the third order nonlinear optical susceptibility for quadratic electro-optic effects for CdS/ZnS/CdS/ZnS core/shell/well/shell spherical quantum dots is realized. Electron energies and corresponding functions are investigated under the frame work of the effective-mass approximation. Then, the third order nonlinear susceptibility is determined using the density matrix method. The dot size effect on this susceptibility is also examined. Numerical calculations confirm that both position and intensity of the peaks can be controlled by varying shell thickness. In addition, by increasing the width of inner or outer shell, the peaks of susceptibility is redshifted and the intensities are increased. Moreover, the 'inverted' structure, ZnS/CdS/ZnS/CdS has shown better nonlinear optical properties.
关键词： third order nonlinear susceptibility,II-VI Semiconductors,Quantum dot quantum well
更新于2025-09-23 15:19:57