ELECTRONIC-STRUCTURES OF THE ALKALI-CONTAINING BUCKMINSTERFULLERENES (A-DELTA-C60) (A=LI,NA,K,RB,CS) AND THE HALOGEN-CONTAINING BUCKMINSTERFULLERENES (H-DELTA-C60) (H=F,CL,BR,I)

The geometrical parameters and electronic structures of C60, (A partial derivative C60) (A = Li, Na, K, Rb, Cs) and (H partial derivative C60) (H = F, Cl, Br, I) have been calculated by the EHMO/ASED (atom superposition and electron delocalization) method. When putting a central atom into the C60 cage, the frontier and subfrontier orbitals of (A partial derivative C60) (A = Li, Na, K, Rb, Cs) and (H partial derivative C60) (H = F, Cl) relative to those of C60 undergo little change and thus, from the viewpoint of charge transfer, A (A = Li, Na, K, Rb, Cs) and H (H = F, Cl) are simply electron donors and acceptors for the C60 cage resPeCtively. Br is an electron acceptor but it does influence the frontier and subfrontier MOs for the C60 cage, and although there is no charge transfer between I and the C60 cage, the frontier and subfrontier MOs for the C60 cage are obviously influenced by I. The stabilities DELTAE(X) (DELTAE(X) = (E(X) + E(C60)) - E(x partial derivative C60)) follow the sequence I < Br < None < Cl < F < Li < Na < K < Rb < Cs while the cage radii r follow the inverse sequence. The stability order and the cage radii order have been explained by means of the (exp-6-1) potential.

THIN-FILM BIPBSRCACUO DIRECT-CURRENT SUPERCONDUCTING QUANTUM INTERFERING DEVICES OPERATING AT 78-K

Direct current SQUIDs (superconducting quantum interference devices) have been successfully fabricated by using a Pb-doped BiSrCaCuO superconducting thin film made by mixed evaporation of a single source composed of related components with a resistance heater. The dc SQUID comprises a square washer with a small hole. These SQUIDs show perfectly periodic voltage-flux characteristics without magnetic shield, that is, typically, the flux noise and energy resolution at a frequency range from dc to 1 Hz and at 78 K being 1.7 x 10(-3) PHI-0/ square-root Hz and 3.6 x 10(-26) J/Hz, respectively. Meanwhile, we have found out that one of the SQUIDs still was able to operate on flux-locked mode without bias currents and showed voltage-flux second harmonic characteristics. This phenomenon is not well understood, but it may be related to I-V (current-voltage) characteristics of the dc SQUID.

Low-temperature (10 K) infrared measurement of interstitial oxygen in heavily antimony-doped silicon via wafer thinning

A new technique is reported for the rapid determination of interstitial oxygen in heavily Sb-doped silicon. This technique includes wafer thinning and low-temperature 10 K infrared measurement on highly thinned wafers. The fine structure of the interstitial oxygen absorption band around 1136 cm(-1) is obtained. Our results show that this method efficiently reduces free-carrier absorption interference, allowing a high reliability of measurement, and can be used at resistivities down to 1 x 10(-2) Omega cm for heavily Sb-doped silicon.

New aspects of K promoted nitridation of the InP(100) surface

The effect of molecular nitrogen exposure on the InP(100) surface modified by the alkali metal K overlayer is investigated by core-level photoemission spectroscopy using synchrotron radiation. The alkali metal covered surface exhibits reasonable nitrogen uptake at room temperature, and results in the formation of a P3N5 nitride complex. Flash annealing at 400 degrees C greatly enhanced the formation of this kind of nitride complex. Above 500 degrees C, the nitride complex dissolved completely. (C) 1997 American Vacuum Society.

PHOTOEMISSION-STUDIES OF K-PROMOTED NITRIDATION AND OXIDATION OF THE INP(100) SURFACE USING SYNCHROTRON-RADIATION

The effect of a potassium overlayer on nitridation and oxidation of the InP(100) surface is investigated by core-level and valence-band photoemission spectroscopy using synchrotron radiation. In comparison with the K-promoted nitridation of the InP(110) surface obtained by cleavage in situ, we found that the promotive effect for the InP(100) surface cleaned by ions bombardment is much stronger and that the nitridation products consist of two kinds of complexes: InPNx and InPNx+y. The results confirmed that surface defects play an important part in the promotive effect. Furthermore, in contrast with K-promoted oxidation of InP(100) where bonding is observed between indium and oxygen, indium atoms did not react directly with nitrogen atoms during the K-promoted nitridation of InP(100). (C) 1995 American Vacuum Society.

PHOTOEMISSION-STUDIES OF K-PROMOTED NITRIDATION OF INP(100) SURFACE USING SYNCHROTRON-RADIATION

The effect of molecular nitrogen exposure on the surfaces of InP(100) modified by potassium overlayers is investigated by core-level and valence-band photoemission spectroscopy using Synchrotron radiation. In comparison with InP(110) surface, we found the promotion is much stronger for InP(100) surface due to the central role of surface defects in the promotion; furthermore, in contrast with K-promoted oxidation of InP(100) where the bonding is observed between indium and oxygen, indium atoms did not react directly with nitrogen atoms during the K-promoted nitridation of InP(100).

光纤位移传感器在77和4.2 K下的输出特性研究

介绍了一种可用于低温装置内的补偿式光纤位移传感器(CFODS),讨论了该传感器在低温下的输出特性并在液氮温度(77 K)和液氦温度(4.2 K)下进行了实验研究.结果表明,该传感器在液氮温度下的灵敏度0.311 mm~(-1),高于液氦温度下的灵敏度0.278 mm~(-1).

VLSI architecture of a K-best detector for MIMO--OFDM wireless communication systems

The K-best detector is considered as a promising technique in the MIMO-OFDM detection because of its good performance and low complexity. In this paper, a new K-best VLSI architecture is presented. In the proposed architecture, the metric computation units (MCUs) expand each surviving path only to its partial branches, based on the novel expansion scheme, which can predetermine the branches' ascending order by their local distances. Then a distributed sorter sorts out the new K surviving paths from the expanded branches in pipelines. Compared to the conventional K-best scheme, the proposed architecture can approximately reduce fundamental operations by 50% and 75% for the 16-QAM and the 64-QAM cases, respectively, and, consequently, lower the demand on the hardware resource significantly. Simulation results prove that the proposed architecture can achieve a performance very similar to conventional K-best detectors. Hence, it is an efficient solution to the K-best detector's VLSI implementation for high-throughput MIMO-OFDM systems.

二元高－k材料研究进展及制备

随着大规模集成电路的发展，需要一种高介质材料来代替传统的SiO2,介绍了可能替代SiO2的几种二元材料的研究现状，主要包括Si3N4,Ta2O5,TiO2,ZrO2,Y2O3,Gd2O3和CeO2几种材料的结构和电学性能，以及制备薄膜的几种方法；蒸发法，化学气相沉积和离子束沉积。

室温下InP（100）表面K诱发催化氮化反应的同步辐射光电子能谱研究

于2010-11-23批量导入

K对InP（100）表面催化氧化反应的同步辐射光电子能谱研究

国家自然科学基金

Photoemission evidence for dilute k-doped phase KxC（60） with x<0.2

于2010-11-23批量导入

Origin of flat-band voltage sharp roll-off in metal gate/high-k/ultrathin- SiO2/Si p-channel metal-oxide-semiconductor stacks

The origin of the flat band voltage roll-off (V-FB roll-off) in metal gate/high-k/ultrathin-SiO2/Si metal-oxide-semiconductor stacks is analyzed and a model describing the role of the dipoles at the SiO2/Si interface on the V-FB sharp roll-off is proposed. The V-FB sharp roll-off appears when the thickness of the SiO2 interlayer diminishes to below the oxygen diffusion depth. The results derived using our model agree well with experimental data and provide insights to the mechanism of the V-FB sharp roll-off.

Fermi-Level Pinning at Metal/High-k Interface Influenced by Electron State Density of Metal Gate

The Fermi-level pinning (FLP) at the metal/high-k interface and its dependence on the electron state density of the metal gate are investigated. It is found that the FLP is largely determined by the distortion of the vacuum level of the metal which is quantitatively ruled by the electron state density of the metal. The physical origin of the vacuum level distortion of the metal is attributed to an image charge of the interface charge in the metal. Such results indicate that the effective work function of the metal/high-k stack is also governed by the electron state density of the metal.