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Study of electron transport in nanopillar transistor at 300K shows that elastic vibration is an intrinsic behavior of the device. The frequency observed in the drain-source current is found to agree with the charging frequency. Given a quantum dot of size 10×10×9nm3, the maximum displacement is estimated to be 0.3nm. Once the displacement diminishes to zero, single-electron tunnel becomes the dominating...
Single electron transistors based on silicon nanopillars were investigated with regard to their current voltage characteristics. The simulations make use of the commercial quantum simulator nextnano++, but extend its functionality for the calculation of tunneling currents. A comparison with results obtained by the Monte-Carlo based tunneling simulator SIMON is presented. Investigations include the...
The non-linear diffusion-deformation theory of self-organization of nanoclusters of dot defects in semiconductor exposed to ultrasound treatment that considers the interaction of defects among themselves and with atoms of a matrix via the elastic field created by dot defects and an acoustic wave is developed. Within this theory the influence of ultrasound on the conditions of formation of spherical...
Semiconductor quantum dots are often proposed as an ideal means to achieve non-linear interactions and photon switching in semiconductor integrated circuits. We examine here the use of the electron spin degree of freedom as a means to achieve a controllable quantum switching of single photons and trains of photons. We examine some types of spin-based quantum switches, and the design principles upon...
We present switching experiments performed on pillar microcavities containing a collection of quantum dots (QDs). Switching events are probed using QD luminescence, after ultrafast optical injection of free carriers. We observe large switching amplitudes (by as much as 20 linewidths), as well as differential switching of the pillar modes under inhomogeneous pumping. Through transient coupling of QDs...
In this paper, the effect of external electric field on the absorption coefficient, emission coefficient and material gain of Quantum Dot ensemble are studied using Fermi's golden rule and considering the Gaussian distribution of density of state due to the deviation of the dot size. The study shows that the electric field causes red-shift in optical transition as well as enhanced optical gain.
We numerically study the effect of carrier grating originated by standing wave pattern on the multi-mode dynamics of semiconductor lasers toward the generation of optical frequency combs. The numerical analysis shows that, due to the localization of the carriers in the quantum dot (QD) active region, the carrier grating guarantees the simultaneous lasing of several optical lines with low mode partition...
Material gain and linewidth of Quantum Dot ensemble are calculated assuming the Gaussian distribution of the density of states due to the size-deviation of dots. The effect of electric field is incorporated in the analysis through the mean and variance of energy states. The results showing the enhancement of optical gain and linewidth with electric field indicate important applications in sub-cellular...
In this study, we developed a filter-free fluorescence image sensor that performed 2D fluorescence imaging without optical filters utilizing the wavelength-dependent absorption depth of a silicon substrate. This sensor changes the potential distribution in the depth direction of the silicon substrate by controlling a potential of the polysilicon gate atop the sensing area. And it can display both...
The registration possibility of the excited states for impurity complexes A+ + e (acceptor with an additional hole, which interacts with an electron, localized in the quantum dot ground state) because of their contribution to the dielectric permeability of the semiconductor quasi-zero structure under intraband optical transitions of electrons in an external magnetic field, has been theoretically analyzed...
We give a classification of the different types of noise in a quantum dot, for variable temperature, voltage and frequency. It allows us first to show which kind of information can be extracted from the electrical noise, such as the ac-conductance or the Fano factor. And next, to classify the mixed electrical-heat noise, and to identify in which regimes information on the Seebeck coefficient, on the...
Colloidal quantum dots (QDs) applied in illuminants and displays have been offered great prospects due to their narrow and tunable emission bands. However, the QD's incompatibility to encapsulant and sensitivities to oxygen and moisture are still limiting their performance in white light emitting diode (WLED). In this research, we have developed a new kind of QDs composites as QDs luminescent microspheres...
This paper investigates the gain dynamics of quantum dot vertical cavity semiconductor optical amplifier (QD-VCSOA) under optical pumping to the wetting layer (WL) and excited state (ES). An equivalent circuit model is developed for analysis of the device characteristics based on the standard rate equations (RE). It is shown that under the WL pumping operation, not only more gain and saturation values...
We investigated fundamental characteristics of a hybrid integrated photoreceiver module with a 1.5 µm-band quantum dot semiconductor optical amplifier (QD-SOA) and conventional pin-photodiode (pin-PD) as a first stage. The results indicated the photoreceiver integrated with a QD-SOA and QD-PD has the potential to be operated for signals over 100 Gb/s.
A monolithically integrated narrow-linewidth (≈ 200 kHz) light source was realized on InP-based quantum dot laser material, which can be tuned over the whole C+ communication band and utilizes the low linewidth enhancement factor as well as the broad gain bandwidth of quasi-zero dimensional gain material.
The effects of quantum dot (QD) ensemble inhomogeneity along with a free-carrier-induced energy shift and homogeneous broadening on the carrier distribution function are studied. Using this model, we show that the dominant factors determining the carrier distribution function are the free carrier effects and not the choice of carrier statistics.
A ridge-waveguide laser with highly stacked InAs quantum dot structure based on strain compensation technique was fabricated. The threshold current of this laser was decreased to approximately 75 mA without coating the facet mirror. A high characteristic temperature of over 100 K was obtained using this laser.
The proposed work explains the absorption property of different material which can be used for the formation of Quantum Dot and their use in solar cells. By using property of Intermediate Band Gap of Quantum Dot efficiency of solar cells can also be increased. Along with it, it's found that absorption of Quantum Dot Depends on the angle by which light falls on them and in most of the cases its maximum...
The electrical and optical properties of InAsP/Si quantum dot solar cell are numerically analyzed in this paper. We have investigated many effects like the number of quantum dot layers inserted, and Arsenic composition of InAsxP1−x on the mains characteristics of a solar cell: Current-Voltage, and the External Quantum Efficiency EQE. It has been shown that Arsenic composition of 60% and 80% provide...
Our work focuses on the simulation and optimization of InSb/GaAs quantum dot solar cell. We have studied the effects of different parameters of the quantum dot such as the number of layers, the thickness and their influence on the solar cell characteristic (Current-Voltage, and the External Quantum Efficiency EQE). Moreover, we have studied the Photoluminescence PL spectra in order to characterize...
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