HeT-SiC-05International Topical Workshop on Heteroepitaxy of 3C-SiC on Silicon and its Application to Sensor DevicesApril 26 to May 1, 2005,Hotel Erbgericht Krippen / Germany- Selected Contributions -

This report collects selected outstanding scientific and technological results obtained within the frame of the European project "FLASiC" (Flash LAmp Supported Deposition of 3C-SiC) but also other work performed in adjacent fields. Goal of the project was the production of large-area epitaxial 3C-SiC layers grown on Si, where in an early stage of SiC deposition the SiC/Si interface is rigorously improved by energetic electromagnetic radiation from purpose-built flash lamp equipment developed at Forschungszentrum Rossendorf. Background of this work is the challenging task for areas like microelectronics, biotechnology, or biomedicine to meet the growing demands for high-quality electronic sensors to work at high temperatures and under extreme environmental conditions. First results in continuation of the project work – for example, the deposition of the topical semiconductor material zinc oxide (ZnO) on epitaxial 3C-SiC/Si layers – are reported too

The importance of hole concentration in establishing carrier-mediated ferromagnetism in Mn doped Ge

In the present work, we have prepared Mn-doped Ge using different annealing approaches after Mn ion implantation, and obtained samples with hole concentrations ranging from 10^18 to 2.1x10^20 cm^-3, the latter being the highest reported so far. Based on the magnetotransport properties of Mn doped Ge, we argue that the hole concentration is a decisive parameter in establishing carrier-mediated ferromagnetism in magnetic Ge.Comment: 7 pages, 3 figure

Comparisioms on growth, physiology and generation of Avicennia marina + Kandelia candel mangroves restored at different tidal elevations

以厦门市曾营海岸的三个人工填土相差0.5m，有相同底质背景的三个滩涂样地（厦零高程3.35、3.74、4.15m）人工种植的白骨壤+秋茄红树林为研究对象，造林4年后，探讨白骨壤和秋茄生长、生理及后代更新的差异。 三个样地红树幼林均密闭成林。从生长上看，白骨壤幼树树高、基径、分枝数、冠幅均为中样地最高，高样地白骨壤树高显著低于低样地，高样地和低样地上的其它指标无显著差异；中样地秋茄幼树树高、基径、分枝数、冠幅最高，高样地上树高和分枝数显著高于低样地，高样地和低样地秋茄幼树基径和冠幅则差异不显著性。中样地白骨壤和秋茄全树年平均生长量及整个样地群落年均增长量最高。从生长的优势上可以推测，中样地（厦...After 4 years’ reforestation, differences in growth and physiological responses of Avicennia marina and Kandelia candel and the next generation updating were studied at three tidal elevations （3.35，3.74，4.15 m of Xiamen sea-level respectively）with 0.5 m intervals，the same sediment background at coastal flat of Zengying, Xiamen. These two mangroves at three tidal elevations were closed 4 years...学位：理学硕士院系专业：海洋与环境学院环境科学与工程系_环境科学学号：2262006115233

A Novel Method to Fabricate Silicon Nanowire p–n Junctions by a Combination of Ion Implantation and in-situ Doping

We demonstrate a novel method to fabricate an axial p–n junction inside <111> oriented short vertical silicon nanowires grown by molecular beam epitaxy by combining ion implantation with in-situ doping. The lower halves of the nanowires were doped in-situ with boron (concentration ~1018cm−3), while the upper halves were doubly implanted with phosphorus to yield a uniform concentration of 2 × 1019 cm−3. Electrical measurements of individually contacted nanowires showed excellent diode characteristics and ideality factors close to 2. We think that this value of ideality factors arises out of a high rate of carrier recombination through surface states in the native oxide covering the nanowires

Quantum communication through a spin chain with interaction determined by a Jacobi matrix

We obtain the time-dependent correlation function describing the evolution of a single spin excitation state in a linear spin chain with isotropic nearest-neighbour XY coupling, where the Hamiltonian is related to the Jacobi matrix of a set of orthogonal polynomials. For the Krawtchouk polynomial case an arbitrary element of the correlation function is expressed in a simple closed form. Its asymptotic limit corresponds to the Jacobi matrix of the Charlier polynomial, and may be understood as a unitary evolution resulting from a Heisenberg group element. Correlation functions for Hamiltonians corresponding to Jacobi matrices for the Hahn, dual Hahn and Racah polynomials are also studied. For the Hahn polynomials we obtain the general correlation function, some of its special cases, and the limit related to the Meixner polynomials, where the su(1,1) algebra describes the underlying symmetry. For the cases of dual Hahn and Racah polynomials the general expressions of the correlation functions contain summations which are not of hypergeometric type. Simplifications, however, occur in special cases

Controllable Growth of Vertically Aligned Graphene on C-face SiC

We investigated how to control the growth of vertically aligned graphene on C-face SiC by varying the processing conditions. It is found that, the growth rate scales with the annealing temperature and the graphene height is proportional to the annealing time. Temperature gradient and crystalline quality of the SiC substrates influence their vaporization. The partial vapor pressure is crucial as it can interfere with further vaporization. A growth mechanism is proposed in terms of physical vapor transport. The monolayer character of vertically aligned graphene is verified by Raman and X-ray absorption spectroscopy. With the processed samples, d0 magnetism is realized and negative magnetoresistance is observed after Cu implantation. We also prove that multiple carriers exist in vertically aligned graphene

Copper gettering at half the projected ion range induced by low-energy channeling He implantation into silicon

He1 ions were implanted at 40 keV into Si channel direction at room temperature (RT) and at 350 °C. The Si samples were subsequently doped with Cu in order to study the gettering of Cu atoms at the defective layer. A subsequent annealing at 800 °C was performed in order to anneal the implantation damage and redistribute the Cu into the wafer. The samples were analyzed by Rutherford backscattering channeling and transmission electron microscopy techniques. The Cu distribution was measured by secondary ion mass spectrometry (SIMS). The SIMS experiments show that, while the 350 °C implant induces gettering at the He projected range (Rp) region, the same implant performed at RT has given as a result, gettering at both the Rp and Rp/2 depths. Hence, this work demonstrates that the Rp/2 effect can be induced by a light ion implanted at low energy into channeling direction