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Influence of Quantum Dot Characteristics on the Performance of Hybrid SET-FET Circuits
摘要： Quantum dots (QDs) can be used as conductive islands to build-up single-electron transistors (SETs). The characteristics of the QDs define the functional performance of the SETs. In consequence, analyzing the influence of the variations of QD dimensions on the performance of hybrid SET-FET circuits is of high relevance. We employ a self-developed SET compact model which is calibrated to 3-D quantum-mechanics-based simulations in order to obtain realistic model parameters. A method to improve the circuit behavior, i.e., to increase the output current, is proposed. It is concluded that the variation of the QD size presents the largest influence on the overall circuit behavior.
关键词： variability,single-electron transistor (SET),quantum dot (QD),Nanowires
更新于2025-09-11 14:15:04
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Ruthenium decorated tungsten disulfide quantum dots for CO2 gas sensor
摘要： In this work, a selective chemi-resistive gas sensor for carbon dioxide gas detection at room temperature (~ 25 °C) was successfully fabricated, where ruthenium decorated tungsten disulfide (Ru@WS2) quantum dots (QDs) have been used as the sensing material. A mixed solvent of lithium hydroxide (LiOH·H2O) and N-Methyl-2-pyrrolidone (NMP) were used to obtain the Ru decorated WS2 QD from the exfoliated WS2 nanoflakes. Then the prepared WS2 QD and Ru@WS2 QD were confirmed using different material characterisation techniques. The gas sensors were then exposed to various concentration of CO2 gas in dry air condition. Also, the effect of humidity of both the sensors in 5000 ppm CO2 gas has been studied. The Ru@WS2 QDs based sensor showed superior sensitivity and good selectivity to CO2 gas in comparison with isopropanol, acetone, ethanol, methanol and benzene at room temperature than WS2 QD. The sensor showed an increase in resistance when exposed to CO2 gas ranging from 500 to 5000 ppm, indicating p-type characteristics. Ru@WS2 QD shows less effect at different humid condition compares to WS2 QD as a CO2 gas sensor.
关键词： Ruthenium decorated tungsten disulfide (Ru@WS2),Transition metal dichalcogenides (TMDC),Quantum Dot (QD),Sensitivity,Selectivity,Gas sensor
更新于2025-09-11 14:15:04
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MODELLING AND SIMULATION OF P-I-N QUANTUM DOT SEMICONDUCTOR SATURABLE ABSORBER MIRRORS
摘要： Semiconductor saturable absorber mirror (SESAM) based on InAs quantum dot (QD) is important in designing fast mode-locked laser devices. A self-consistent time-domain material travelling-wave (TDTW) model for the simulation of self-assembled QD-SESAM is developed. The 1-D TDTW model takes into consideration the time-varying QD optical susceptibility, refractive index variation resulting from the intersubband free-carrier absorption, homogeneous and inhomogeneous broadening. The carrier concentration rate equations are considered simultaneously with the travelling wave model. The model is used to analyze the characteristics of 1.3-μm p-i-n QD InAs-GaAs SESAM. The ?eld distribution resulting from the TDTW equations, in both the SESAM absorbing region and the distributed Bragg re?ectors, is obtained and used in ?nding the device characteristics including the modulation depth and recovery dynamics. These characteristics are studied considering the e?ects of QD surface density, inhomogeneous broadening, the number of QD absorbing layers, and the applied reverse voltage. The obtained results, based on the assumed device parameters, are in good agreement, qualitatively, with the experimental results.
关键词： Travelling-wave model,Quantum dot,Modulation depth,Semiconductor saturable absorber mirror,Recovery dynamics
更新于2025-09-11 14:15:04
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Effect of Self-Induced Transparency in a Massive of Spherical Quantum Dots Under the Conditions of Strong Dimensional Quantization
摘要： The influence of dimensional quantization on the process of self-induced transparency in the system of spherical quantum dots in the frames of the model of the simplest interband transition in the symmetrical spherical infinitely deep wall is considered. Expressions describing the evolution of the energy of ultraviolet pulses are obtained. The relative energy losses when it becomes the 2π-pulse during propagation in a nanoscale medium, and also the polarization of the medium of non-homogeneous broadening, caused by the dispersion of radius of spherical quantum dots are obtained. The case when the radial distribution is described by the Lifshitz-Slyozov formula is considered.
关键词： quantum dot,self-induced transparency,nanostructure
更新于2025-09-11 14:15:04
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[IEEE 2019 IEEE Photonics Conference (IPC) - San Antonio, TX, USA (2019.9.29-2019.10.3)] 2019 IEEE Photonics Conference (IPC) - An Investigation on Stable and Continuous Operation of Hybrid Perovskite Quantum Dot Light Emitting Diodes
摘要： Two different package structures of hybrid perovskite quantum dots light emitting diodes were demonstrated with stable and continuous light emission. With boron nitride nanoparticles, the lifetime of device is expected to be thousands of hours.
关键词： Nanomaterials,Quantum-dot devices,Light-emitting diodes
更新于2025-09-11 14:15:04
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Suppressing Interfacial Dipoles to Minimize Open‐Circuit Voltage Loss in Quantum Dot Photovoltaics
摘要： Quantum-dot (QD) photovoltaics (PVs) offer promise as energy-conversion devices; however, their open-circuit-voltage (VOC) deficit is excessively large. Previous work has identified factors related to the QD active layer that contribute to VOC loss, including sub-bandgap trap states and polydispersity in QD films. This work focuses instead on layer interfaces, and reveals a critical source of VOC loss: electron leakage at the QD/hole-transport layer (HTL) interface. Although large-bandgap organic materials in HTL are potentially suited to minimizing leakage current, dipoles that form at an organic/metal interface impede control over optimal band alignments. To overcome the challenge, a bilayer HTL configuration, which consists of semiconducting alpha-sexithiophene (α-6T) and metallic poly(3,4-ethylenedioxythiphene) polystyrene sulfonate (PEDOT:PSS), is introduced. The introduction of the PEDOT:PSS layer between α-6T and Au electrode suppresses the formation of undesired interfacial dipoles and a Schottky barrier for holes, and the bilayer HTL provides a high electron barrier of 1.35 eV. Using bilayer HTLs enhances the VOC by 74 mV without compromising the JSC compared to conventional MoO3 control devices, leading to a best power conversion efficiency of 9.2% (>40% improvement relative to relevant controls). Wider applicability of the bilayer strategy is demonstrated by a similar structure based on shallow lowest-unoccupied-molecular-orbital (LUMO) levels.
关键词： band engineering,quantum dot solar cells,interfacial dipole,hole transport layers
更新于2025-09-11 14:15:04
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Dopant-Free Squaraine-Based Polymeric Hole-Transporting Materials with Comprehensive Passivation Effects for Efficient All-Inorganic Perovskite Solar Cells
摘要： Quantum-dot (QD) white light-emitting diodes (LEDs) are promising for illumination and display applications due to their excellent color quality. Although they have a high quantum yield close to unity, the reabsorption of QD light leads to high conversion loss, significantly reducing the luminous efficacy and stability of QD white LEDs. In this report, SBA-15 mesoporous particles (MPs) with two-dimensional hexagonal pore structures (2D-HPS) are utilized to largely enhance the luminous efficacy and color-conversion efficiency of QD white LEDs in excess of 50%. The reduction in conversion loss also helps QD white LEDs to achieve a lifetime 1.9 times longer than that of LEDs using QD-only composites at harsh aging conditions. Simulation and testing results suggest that the waveguide effect of 2D-HPS helps in reducing the reabsorption loss by constraining the QD light inside the wall of 2D-HPS, decreasing the probability of being captured by QDs inside the hole of 2D-HPS. As such, materials and mechanisms like SBA-15 MPs with 2D-HPS could provide a new path to improve the photon management of QD light, comprehensively enhancing the performances of QD white LEDs.
关键词： stability,two-dimensional hexagonal pore structure,reabsorption,luminous efficacy,SBA-15 mesoporous particle,quantum-dot white light-emitting diode
更新于2025-09-11 14:15:04
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P‐8.4: A Novel Non‐barrier‐film Quantum Dot Diffusion Plate in Backlight System
摘要： Compared with traditional LED backlight source, the quantum dot-based backlight module has recently attracted extensive interest owing to their wider color gamut. Generally, quantum dots are sensitive to the external environment, and quantum dots in current commercial quantum dot film are usually protected by two barrier film layers to isolate the influence of external factors such as water and oxygen. In this report, a new quantum dot plate strategy was three-layer co-extrusion method developed by a without the use of any expensive barrier film. Quantum dots were homogeneous embedded in the polymeric matrix of the middle layer, and the upper and lower layer act as protective layers to avoid the destruction of external environment to quantum dots. Reliability tests demonstrate that this non-barrier-film quantum dot plate shows satisfactory stability comparable high-barrier-material-based quantum dot films under conditions of blue-LED irradiation, high temperature and high humidity.
关键词： Optical Plate,Backlight,Quantum Dot,Extrusion,Wide-Color-Gamut
更新于2025-09-11 14:15:04
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Monte Carlo model incorporating many-body effects for determining the gain spectra of quantum dot lasers
摘要： We present a Monte Carlo model that simulates the gain spectra of a QD laser material that empirically includes free-carrier effects. We compare simulation results of both Fermi–Dirac and random carrier populations, and compare them with experimental data. The free-carrier effects are highlighted as being more important than the choice of carrier statistics, and routes to improve this simple model are discussed.
关键词： many-body effects,free-carrier effects,Monte Carlo model,gain spectra,quantum dot lasers
更新于2025-09-11 14:15:04
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Quantum dot thermometry at ultra-low temperature in a dilution refrigerator with a <sup>4</sup> He immersion cell
摘要： Experiments performed at a temperature of a few millikelvins require effective thermalization schemes, low-pass filtering of the measurement lines, and low-noise electronics. Here, we report on the modifications to a commercial dilution refrigerator with a base temperature of 3.5 mK that enable us to lower the electron temperature to 6.7 mK measured from the Coulomb peak width of a quantum dot gate-defined in an [Al]GaAs heteostructure. We present the design and implementation of a liquid 4He immersion cell tight against superleaks, implement an innovative wiring technology, and develop optimized transport measurement procedures.
关键词： quantum dot thermometry,ultra-low temperature,dilution refrigerator,4He immersion cell
更新于2025-09-11 14:15:04