Semiconductor arrayed waveguide gratings for photonic integrated devices

This paper reviews recent progress of the semiconductor arrayed waveguide gratings (AWGs) and the integrated semiconductor optical devices including the semiconductor AWGs. Recent research enables us to make semiconductor AWGs with sufficiently low insertion loss and polarization dependence. Using the semiconductor AWGs as core components, the integrated semiconductor optical devices are developing by integrating with the other semiconductor devices including photodetectors, optical amplifiers, and electroabsorption modulators.     

Towards realistic time-resolved simulations of quantum devices

We report on our recent efforts to perform realistic simulations of large quantum devices in the time domain. In contrast to d.c. transport where the calculations are explicitly performed at the Fermi level, the presence of time-dependent terms in the Hamiltonian makes the system inelastic so that it is necessary to explicitly enforce the Pauli principle in the simulations. We illustrate our approach with calculations for a flying qubit interferometer, a nanoelectronic device that is currently under experimental investigation. Our calculations illustrate the fact that many degrees of freedom (16,700 tight-binding sites in the scattering region) and long simulation times (9500 times the inverse bandwidth of the tight-binding model) can be easily achieved on a local computer.     

The Rashba effect and non-Abelian phases in quantum wire devices

We present a 2D method for studying quantum transport through arbitrary geometries under the influence of both external magnetic fields and Rashba spin-orbit coupling. We apply this method to two geometries—a straight wire and a ring structure. Our results reveal the precession of spin-polarized modes in the straight wire, and conductance resonances in the ring due to phase shifts from the magnetic field and from the Rashba effect. The conductance resonances arising from the Rashba effect are due to the non-Abelian nature of the phase shifts acquired by electrons propagating around the ring.     

Component mode synthesis approaches for quantum mechanical electrostatic analysis of nanoscale devices

In this paper, two component mode synthesis (CMS) approaches, namely, the fixed interface CMS approach and the free interface CMS approach, are presented and compared for an efficient solution of 2-D Schr?dinger-Poisson equations for quantum-mechanical electrostatic analyses of nanostructures and devices with arbitrary geometries. In the CMS approaches, a nanostructure is divided into a set of substructures or components and the eigenvalues (energy levels) and eigenvectors (wave functions) are computed first for all the substructures. The computed wave functions are then combined with constraint or attachment modes to construct a transformation matrix. By using the transformation matrix, a reduced-order system of the Schr?dinger equation is obtained for the entire nanostructure. The global energy levels and wave functions can be obtained with the reduced-order system. Through an iteration procedure between the Schr?dinger and Poisson equations, a self-consistent solution for charge concentration and potential profile can be obtained. Numerical calculations show that both CMS approaches can largely reduce the computational cost. The free interface CMS approach can provide significantly more accurate results than the fixed interface CMS approach with the same number of retained wave functions in each component. However, the fixed interface CMS approach is more efficient than the free interface CMS approach when large degrees of freedom are included in the simulation.     

A numerical method for a transient quantum drift-diffusion model arising in semiconductor devices

This paper describes a numerical method for a transient quantum drift-diffusion model arising in semiconductor devices. The discretization method is presented with emphasis on adaptive time discretization. An adaptive time step algorithm is constructed by introducing the derivative of the free energy of the system, which has an essential property to understand the carrier behavior of the time-dependent problems. The algorithm is verified with switching characteristics of one-dimensional n⁺–n–n⁺ silicon diodes. It is shown that the time step is adapted to the switching characteristics. The new algorithm significantly reduces the total number of time steps.     

Density-gradient theory: a macroscopic approach to quantum confinement and tunneling in semiconductor devices

Density-gradient theory provides a macroscopic approach to modeling quantum transport that is particularly well adapted to semiconductor device analysis and engineering. After some introductory observations, the basis of the theory in macroscopic and microscopic physics is summarized, and its scattering-dominated and scattering-free versions are introduced. Remarks are also given about the underlying mathematics and numerics. A variety of applications of the theory to both quantum confinement and quantum tunneling situations are then reviewed. In doing so, particular emphasis is put on understanding the range of validity of the theory and on its unexpected power as a phenomenology. The article closes with a few comments about the future.     

Electronic and excitonic processes in multilayer organic light emitting devices incorporating PbSe quantum dots

In this work we investigate the operation mechanism of hybrid organic/inorganic quantum dot light emitting devices (QD-LEDs). We employ a numerical method previously established to describe current-voltage characteristics, spatial distributions of charge, electric field, and recombination rate in organic light emitting devices (OLEDs). The numerical solution of the continuity and Poisson equations have been extended to treat internal organic/Quantum Dot (QD) interfaces, recombination processes in the polymer matrix and in the QDs, and the charge acquired by the QDs. The contact boundary condition is taken to be Schottky contact boundary condition. Also, we consider the exciton formation and diffusion processes. The simulation results trend and experimental data are in good agreement.     

3D Monte Carlo simulation of FinFET and FDSOI devices with accurate quantum correction

The performance of FinFET and FDSOI devices is compared by 3D Monte Carlo simulation using an enhanced quantum correction scheme. This scheme has two new features: (i) the quantum correction is extracted from a 2D cross-section of the 3D device and (ii) in addition to using a modified oxide permittivity and a modified work function in subthreshold, the work function is ramped above threshold to a different value in the on-state. This approach improves the accuracy of the quantum-correction for multi-gate devices and is shown to accurately reproduce 3D density-gradient simulation also at short channel lengths. 15 nm FDSOI device performance with thin box and back-gate bias is found to be competitive: compared to a FinFET with (110)/〈110〉 sidewall/channel orientation, the on-current for N-type devices is 25 % higher and the off-current is only increased by a factor of 2.5.     

电源管理半导体

电源管理半导体是一种新型的电力电子器件,它将功率集成电路进一步延伸,将一些外围电路及控制(可编程)融为一体.为各类电器尤其是便携式电器的电源提供广泛而方便的选择.电源管理半导体具有高集成化、高智能化和模块化的特点,它在电子领域的优异表现,必将对电力电子装置产生革命性的影响,电力电子功能模块(PEBB)的出现就是其中一个很好的范例.     

Effects of Mg dopant on the degradation of InGaN multiple quantum wells in AlInGaN-based light emitting devices

We investigated the effects of Mg dopant on the degradation of AlInGaN-based light emitting diodes (LEDs) and laser diodes (LDs) with InGaN multi-quantum wells (MQWs). Photoluminescence (PL) intensity of InGaN MQWs was significantly decreased with increasing the Mg intentional doping process in InGaN active region, indicating that Mg dopant could degrade the optical quality of InGaN MQWs. From secondary ion mass spectroscopy (SIMS) analysis of AlInGaN-based LDs grown on GaN/sapphire and GaN substrate with different dislocation densities, we found that Mg concentration of LD on GaN/sapphire was higher than that of LD on GaN substrate at the InGaN MQWs regions. Additionally, we observed that Mg atoms were significantly diffused from p-type layer to InGaN MQWs region in the LD structure after aging evaluation. From these results, we could conclude that Mg diffusion along threading dislocations is one of the major gradual degradation mechanisms of AlInGaN-based LD/LEDs during the device operation under high voltage condition.     

半导体照明的曙光

本文主要介绍了用于指示、装饰照明等LED的发展,对白光LED进行了研究,大功率LED的特点,虽然LED作为普通照明还有一定的距离,但我们已经看到了半导体照明的曙光.     

A Semiconductor Technology Course

A one-year semiconductor technology course for undergraduate senior electrical engineering students is described. The course consists of one semester of lecture followed by one semester of laboratory. The material covered in the lecture is demonstrated to the students by field trips to local industry and in their laboratory. Highly sophisticated technology such as ion-implantation is demonstrated in field trips and technology such as thermal diffusion is encountered by the student in his laboratory course. "Thus, whenever possible, the student can relate his lecture material to observation. The laboratory consists of a complete processing operation where the student starts with a crystal boule and fabricates a packaged device whose terminal characteristics are measured. He or she thus obtains some feeling for the effects of processing on terminal characteristics. Projects are used in conjunction with the laboratory to improve some of the process steps and to give the student some experience in tackling nonstructured problems which are more closely related to professional activities after graduation.     

Semiconductor optical space switches

This paper reviews the various optical space switch structures on III-V semiconductor material. Their characteristics are discussed in the context of optical transport and switching network applications exploiting wavelength division multiplexing     

LED照明——半导体的又一次革命

三十年LED指示与显示技术逐渐成熟，在交通信号灯和汽车尾灯等单色光的应用领域迅速取代了白炽灯，而且近来又突破单一颜色的局限性向白色光照明迈进，该文对LED的工作原理，发展历史及现状进行了分析，并预言2005年，2010－2015年LED灯光效将分别达到50lm/w和150－200lm/w。     

半导体在电力技术中的应用

传统电网通常围绕着大型集中式发电厂建设,发电厂以稳定方式向电网提供可预测、可控制的电能.作为响应需求.潮流每小时都有涨落,电网中始终保持着单向的电力潮流.     

Modeling of Semiconductor Optical Amplifiers

We present a tight-binding analysis of the polarization dependence of GaAs -strained semiconductors optical amplifiers. We explain how thin strained GaAs layers embedded in a lattice-matched InGaAsP/InGaAs quantum well can be used to achieve polarization insensitive optical amplification. We describe also the interaction between pulse propagation and gain compression within a pump-probe excitation in polarization insensitive MQW-SOA. Another important non-linear effect studied is Four Wave Mixing (FWM) on the pulse propagation in the active region of SOAs. Our model successfully predicts operation of optical data sampling using FWM interaction between a signal bit stream and an optical clock.     

Semiconductor technologies for higher frequencies

The millimeter wavelength range (30-300 GHz) is not well exploited, except for its lower part. New applications in imaging, security, medicine, and short-range wireless transmission as well as the ever increasing data rates of optical fiber transmission could alter this situation rather quickly [1], [2]. During the last three decades, III-V technologies (GaAs and InP) have progressively expanded throughout this millimeter wave area. More recently, and owing to the continuous scaling of processes, silicon technologies have also entered the game.     

半导体PWM变压器的开发

根据我国电力变压器行业的发展水平和电力行业发展需要,提出开发新一代半导体变压器。并结合当今电力电子技术的发展水平,对其作了可行性分析。     

DC Fusing in Semiconductor Circuits

The development of power semiconductors and their application in the past few decades has brought about new requirements for their protection by fuses. In a large number of applications the fuse has to interrupt a direct-current fault. These applications include chopper circuits, regenerative dc drives, battery supplies, traction applications, and inverter circuits used in variable-speed ac drives and uninterruptible power supplies. Guidance is provided on fuse selection in typical circuits.     

An Undergraduate Semiconductor Device Laboratory

A semiconductor device laboratory course is described which has been developed as a senior technical elective. The objectives of the course are to strengthen the experimental understanding of abstract solid-state parameters, to weight the overall curriculum somewhat less heavily in abstractions, and to provide background for more advanced experimental work either in graduate school or in industry.