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We study the strain profiles of Type-I CdS/CdSe quantum ring (QR) using the Valence force field method with Keating potential. The strain affects its electronic bandstructure which is calculated for varying QR widths using an effective mass envelope function theory based 8-band k·p model. This is followed by an electron-hole charge distribution study of the QR.
Optical absorption is an important characteristic of CdSe nanoplatelets (NPLs) used for optoelectronic applications. Here, we theoretically investigate the absorption spectra of CdSe NPLs considering Sommerfeld enhancement and excitonic effects and study its relation with the electronic structure and optical transition matrix elements.
Group IV (Si, Ge, Sn) alloys are promising materials for future optoelectronic devices. Their compatibility with Si technology would allow us to engineer novel growth techniques and bandgap engineering methods to obtain direct band gap materials [1]. Other alloy compositions could allow wider wavelength range [2] which can revolutionize the photonics industry - leading to new design of LEDs, photodetectors,...
Li-ion battery is becoming the optimal choice for EV's power supply. In order to keep the Li-ion battery away from charging damage and prolong the battery's life, we present and evaluate here a special control strategy based on dynamic balanced point along with a non-dissipative equalizer. The main focus of the proposed control strategy is to insure that individual cell of a battery pack will be rapidly,...
Lithium-ion battery voltage equalization is of great importance to maximize the capacity of the whole battery pack and keep cells away from over-charge or over-discharge damage.In this paper, analysis of the working principle of the voltage equalization circuit shows that the speed of the lithium-ion battery cells voltage equalization can be accelerated with optimized circuit parameters. Look- up...
The electronic band structures and optical gains of Ge/SixSnyGe1−x−y truncated pyramid-shaped quantum dots (QDs) are calculated using the 8-band k.p model. The large bowing factors in the calculation of band gaps of both Ã-conduction and L-conduction valley in the barrier are considered so that the band gaps of the barrier are small. The strains are calculated by constant strain method and valence...
Among methods modeling electronic structures of low dimensional heterostructures, such as first principles, tight binding, k·p, etc., the multiband k·p method is the most effective for low dimensional systems with a big compilation of atoms such as quantum dots. Numerical implementation like the finite difference method and the finite element method engages differential or integral process and thus...
We present a systematic study of different sonicated cold development scenarios for the purpose of achieving high density optical metamaterial. High aspect ratio sub-15-nm dots at pitch as small as 40 nm are successfully demonstrated for 110-nm thick resist at low exposure dose. Some of the key results include sub-15-nm gold nanodots at 40-nm pitch and high density optical metamaterial (with only...
The method of quality monitor based on wavelet filtering was proposed to solve the problems of quality control in multi-operation manufacturing processes, whose measurement data contained noise information. The multi-operation machining process quality control model based on the Stream of Variation (SoV) technology was built, which considered the error propagation. Based on this, the method of discrete...
This paper proposes a simple but effectual method to alleviate the voltage stress of the rectifier and improves the overall efficiency of the conventional PSFB converter. This method is based on such a factor that the equivalent circuit of the PSFB converter during the voltage oscillation period can be treated as a fifth-order model, and thus, the amplitude of the voltage ringing across the rectifier...
This work reports the experimental quantifications of coupling-induced phase shift (CIPS) in various resonant structures fabricated in silicon-on-insulator technology, and confirms the counter-intuitive results that CIPS may change sign at increasing gap separation.
We present a simple approach for sub-30nm dielectric and metal patterning based on low voltage electron beam lithography and standard lift-off process by using 42nm hydrogen silsesquioxane and 200nm ZEP resist.
We demonstrate coupled-resonator induced transparency by means of synergistic integration between the ring-bus-ring (RBR) configuration and the Mach-Zehnder interferometer (MZI) device, on silicon-on-insulator (SOI) material platform. Good agreement is obtained between experiment and the theory.
A low noise amplifier with dB-linear variable gain has been designed and fabricated based on high performance SiGe HBT in this paper. Negative feedback technology has been adopted to change the transmission gain of HBT through variable resistance of a forward biased p-i-n diode in the feedback path. The simulation results and measurement results agree well in frequency of 1.8GHz for CDMA application...
From semiconductor quantum well structures to the currently hottest metamaterials, the conquest of nano-world has been occurring in almost every field of research. In the field of quantum well structures for infrared photodetection, the inclusion of dilute nitride layers in the mature GaAs based quantum well structures results in a TE dominate photocurrent and the incorporation of nitrogen in the...
We present a theoretical study on mechanism of redshift in InAs/InxGa(1-x)As quantum dots, of which redshift is realized via controlling In composition x and lower confining layer thickness t to ease up the enlargement of band gap due to strain. Introducing In component in the confining layer material leads to significant redshift but thermal quenching due to waning band discontinuity, therefore proper...
We develop the temporal coupled mode theory for the ring-bus-ring device by taking account of the energy-conservation. The presence of the center waveguide in the tri-coupler section of the RBR facilitates the interaction between the two side-coupled rings. The correspondence between the coupled mode theory in time and transfer matrix formalism (TMF) is established. A very good agreement is obtained...
This paper provides a vibration-based diagnostic platform to systematically monitor and diagnose of rotary machine faults. Commonly rotary machine faults described in this paper are misalignment fault, bearing cage defect, ball bearing defect, bearing outer race fault and inner race fault. The use of structural resonance frequency, ISO 10816 for vibration level assessment, spectrum assessment for...
A theoretical analysis of wetting layer effect on electronic structures of InAs/GaAs truncated-pyramid quantum dots is carried out using an eight-band Fourier transform-based k·p method. Wetting layer changes ground-state energy significantly whereas modifies probability density function only a little. The main acting region of wetting layer is just underneath the base of the dot.
Three advanced direct contact via processes with Ta/TaN/Ta tri-layer barrier and the electromigration of their structures were comparatively investigated. The process of Ar+ resputtering with median removal of tri-layer barrier shows the lowest defective die percentage. It also shows the highest activation energy and longest downstream electromigration lifetime.
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