Spin-Hall transport in a two-dimensional electron system with magnetic impurities

The spin Hall transport properties in a two-dimensional electron system with both Rashba spin-orbit coupling (SOC) and magnetic impurities are investigated. Electrons are scattered by impurities through an exchange interaction that leads to spin flip-flop processes and so changes the spin Hall effect induced by the SOC. The spin Hall conductance is calculated in a 4-terminal system using the Landauer-Buttiker formula and Green function approach. In comparison with the simulation results on nonmagnetic impurities doping systems, our results reveal that the spin Hall conductance is still nonzero in a system with a large density of magnetic impurities and a finite intensity of the exchange interaction between the electrons and impurities, and its sign may be altered when the doping density and interaction strength are large enough.     

SiC单晶生长技术及器件研究进展

综述了近年来国外ＳｉＣ单晶及外延层生长、分立器件和集成电路的研究进展情况。     

Molecular dynamics study on the field effect ion transport in carbon nanotube

We investigated potassium ion transport in the (5, 5) carbon nanotube by using classical molecular dynamics simulations under applying external force fields. This can be applied to nanoscale ionic-field-effect devices. As the applying external force field increases, the potassium ions rapidly go through the nanochannel. Under the low external force fields, the thermal fluctuation of the nanochannel affected on the tunneling of the potassium ions, whereas the effects of the thermal fluctuation were negligible under the high external force fields.     

Molecular image-processing devices based on chemical reaction systems. I: General principles for implementation

Potentialities for implementing simple neural information-processing devices based on chemical and biochemical dynamical media are discussed. Pilot ‘hardware’ models of neural molecualr devices that able to perform image-processing operations were constructed.     

Optoelectronic Thresholder for Pattern Recognition with Double Feedback Module

The present paper proposes a modification of a simple optoelectronic architecture (A. Bergeron et al.: Appl. Opt. 33 (1994) 1463) for carrying out optical thresholding operations. The threshold operation is achieved by means of a feedback loop. The setup is modified by inserting an attenuator adapted in each iteration to the total incident energy measured by an intensity detector. The proposed architecture does not need an additional light source, assures translation invariance and does not break the beam propagation path. The adaptive attenuator permits working under different lighting conditions (illumination, partially occluded objects, etc.). This kind of architecture is suitable for an optical pattern recognition task, optical neural network or optical associative memory. Application of the modified thresholder to the recognition task based on an optical correlator is reported.     

金刚石薄膜半导体器件

介绍了金刚石薄膜的性质、当今金刚石薄膜半导体器件的技术、水平和性能。分析了金刚石薄膜作为半导体器件的优异性能、金刚石相对于硅的半导体器件性能的改善和存在的问题，并指出实现金刚石薄膜半导体器件的障碍。     

Optoelectronic Butterfly Interconnection Implementation of an n-bit Parallel Full Addition and Subtraction

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影响GaAs-GaAlAs相位调制器的相位移效率因素的研究

本文报道了腐蚀脊型GaAs-GaAlAs双异质结相位调制器,研究了反向偏压、测试光源波长和波导层载流子浓度对器件相位移效率的影响,得到了迄今最高的相位移效率的结果.     

Fourier-inversion and wavelet-transform methods applied to X-ray reflectometry and HRXRD profiles from complex thin-layered heterostructures

We show that X-ray scattering techniques can be used for the assessment of individual layer thicknesses inside complicated semi-conductor heterostructures dedicated to the opto-electronic domain. To this end, we propose methods to overcome two main drawbacks coming from: (1) the complexity of the X-ray profiles and, hence the difficulty to use model-dependent tools such as fitting procedures and (2) large dynamics in intensity due to numerous high diffraction superlattice peaks from superlattices which limit the use of the model-independent Fourier-inversion method.We demonstrate first the reliability of the Fourier-inversion method applied to high-resolution X-ray diffraction profiles curve from quantum well infrared photodetectors heterostructures, complementary to the model-dependent fitting tools. Then, a wavelet-transform-based procedure has been successfully used on X-ray reflectometry profiles containing intense SL Bragg peaks.     

Pb1−xSnxSe-on-Si LWIR sensor arrays and thermal imaging with JFET/CMOS read-out

Long wavelength infrared (LWIR) sensor arrays were fabricated in Pb_1−xSn_xSe layers grown epitaxially on Si-substrates by MBE. A CaF2 intermediate buffer layer ≈30dgA thick was employed for compatibility reasons. The photovoltaic sensors are based on the blocking Pb-contact technique on p-type material. They were fabricated using simple wet-etching process steps only. Cut-off wave-lengths were about 10.5 μm, quantum efficiencies >60%, and resistance-aera products above 3 Ω-cm² at 90K. A demonstrational LWIR thermal imaging camera was assembled with a 256 element line array with 50 μm pitch. Low-noise signal processing was achieved with sensors with differential resistances in the 10 kOhm range by using JFET/CMOS technology. For each channel, an integrator, correlated multiple sampling and sample/hold amplifier was used before multiplexing to a common output.