排序方式: 共有218条查询结果,搜索用时 15 毫秒
61.
H. El-Sayed 《Applied Surface Science》2007,253(22):8962-8968
Direct selective metal deposition on semiconductors is of interest to electronic device technology, in particular for interconnects and Schottky devices. In this study, we investigate selective copper electrodeposition on patterned tantalum oxide thin films. Cyclic voltammetry studies show that thick tantalum oxide thin films have insulating properties while oxide films thinner than a critical value are semiconductors. Copper films electrodeposited on tantalum oxide thin films are known to form Schottky contacts. We demonstrate the formation of copper patterns on pre-patterned tantalum oxide films by a simple process: an insulating tantalum oxide film was grown electrochemically, the film was then mechanically scratched followed by mild oxidation to produce a thin tantalum oxide film inside the scratch. Based on the differential behavior of thin and thick tantalum oxide films, metal lines were electrodeposited selectively under formation of Schottky junctions. The process demonstrated in this paper is compatible to standard processes for semiconductor device fabrication while permitting flexible prototyping for research at small scales. 相似文献
62.
ZnO thin films were electrochemically deposited onto the ITO-coated glass substrate from an electrolyte consisted of 0.1 M Zn(NO3)2 aqueous solution at 65 ± 1 °C. A compact ZnO film with (0 0 2) preferred orientation was obtained at the applied potential of −1.3 V for 1200 s. It was also found that the morphology of the ZnO films grown at the potential of −1.3 V was characterized of single or coalescent hexagonal platelets. However, the ZnO crystals grown at the potential of −2.0 V was changed to be a bimodal size distribution. The band gap energy of the as deposited ZnO films, about 3.5 eV, was independent of both the applied potential and the deposition time, respectively. The minor amount of Zn(OH)2 might be co-deposited with the formation of ZnO revealed by the FT-IR spectroscopy. Three strategies to improve the ZnO crystal quality based on the photoluminescence properties were proposed in the paper, which were (a) adopting the lower deposition potential, (b) increasing the deposition time at a certain potential, and (c) annealing after as-deposition, respectively. 相似文献
63.
A. Csordás É. Szöke P. Szépfalusy 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(1):113-124
The paper deals with the ground state structure of the partly filled l-shell
of a fermionic gas of atoms of spin s in a spherically
symmetric spin independent trap potential. At particle
numbers N=n(2s+1), n=1,2,...,2l+1 the basic building blocks
are clusters consisting of (2s+1) atoms, whose wave functions
are completely symmetric and antisymmetric in space and spin variables,
respectively.
The creation operator of a cluster is constructed and applied also to
create multi cluster states.
Ground state energy expressions are derived for the
n-cluster states at different l, s values and interpreted in simple terms. 相似文献
64.
Improved Performance of Organic Thin Film Transistor with an Inorganic Oxide/Polymer Double-Layer Insulator 下载免费PDF全文
We employ the Ta2Os/PVP (poly-4-vinylphenol) double-layer gate insulator to improve the performance of pentacene thin-film transistors. It is found that the double-layer insulator has low leakage current, smooth surface and considerably high capacitance. Compared to Ta205 insulator layers, the device with the Ta2Os/PVP doublelayer insulator exhibits an enhancement of the field-effect mobility from 0.21 to 0.54 cm2/Vs, and the decreasing threshold voltage from 4.38 V to -2.5 V. The results suggest that the Ta2Os/PVP double-layer insulator is a potential gate insulator for fabricating OTFTs with good electrical performance. 相似文献
65.
We investigate the spin-dependent effective electron-electron interactions in a uniform system of two-dimensional electrons to understand the spontaneous magnetization expected to occur at very low density. For this purpose, we adopt the Kukkonen-Overhauser form for the effective interactions which are built by accurately determined local-field factors describing the charge and spin fluctuations. The critical behavior of the effective interaction for parallel spin electrons allows us to quantitatively locate the transition to the ferromagnetic state at rs≈27. When the finite width effects are approximately taken into account the transition occurs at rs≈30 in agreement with recent quantum Monte Carlo calculations. 相似文献
66.
James S. Cooper 《Applied Surface Science》2007,254(3):662-668
An improved fuel cell cathode catalyst composition was pursued by fabricating and screening thin film combinatorial libraries. Results from the Pt-Ru, Pt-Co-Ti, Pt-Co-Cu and Pt-Co-Cr systems are reported. The discrete composition combinatorial libraries were fabricated by plasma sputtering through shadow masks. Each combinatorial library was tested by cyclic voltammetry in a multichannel electrochemical cell. Compositions were ranked based on the onset potential of the oxygen reduction reaction. Several compositions exhibited better onset potentials than pure Pt. The optimum composition from the Pt-Co-Ti system was Pt44Ti12Co44 but showed signs of corrosion after prolonged testing. A wide range of Pt-Co-Cu compositions also outperformed Pt initially, but ultimately failed due to poor corrosion resistance. Among all of the compositions that were screened, the best performance was demonstrated by Pt28Co36Cr36, with an onset potential 107 mV higher than pure Pt and no sign of corrosion. 相似文献
67.
C.M. Bordogna E.V. Albano 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,25(3):391-396
A model for teaching-learning processes that take place in the classroom is proposed and simulated numerically. Recent ideas
taken from the fields of sociology, educational psychology, statistical physics and computational science are key ingredients
of the model. Results of simulations are consistent with well-established empirical results obtained in classrooms by means
of different evaluation tools. It is shown that students engaged in collaborative groupwork reach higher achievements than
those attending traditional lectures only. However, in many cases, this difference is subtle and consequently very difficult
to be detected using tests. The influence of the number of students forming the collaborative groups on the average knowledge
achieved is also studied and discussed.
Received 22 October 2001 相似文献
68.
Copper nanowire arrays for infrared polarizer 总被引:10,自引:0,他引:10
Y.T. Pang G.W. Meng Y. Zhang Q. Fang L.D. Zhang 《Applied Physics A: Materials Science & Processing》2003,76(4):533-536
A micropolarizer of copper nanowire arrays within anodic alumina membrane (AAM) was fabricated by anodization of pure Al foil
and electrodeposition of Cu, respectively. X-ray diffraction, scanning electron microscopy and transmission electron microscopy
investigations reveal that the ordered Cu nanowires are essentially single crystal, and have an average diameter of 90 nm.
Spectrophotometer measurements show that the copper nanowire arrays embedded in AAM can only transmit polarized light vertical
to the wires. An extinction ratio of 24 to 32 dB and an average insertion loss of 0.5 dB in the wavelength range of 1 to 2.2 μm
were obtained, respectively. Therefore Cu nanowire/AAM can be used as a wire grid type micropolarizer.
Received: 28 January 2002 / Accepted:17 May 2002 / Published online: 22 November 2002
RID="*"
ID="*"Corresponding author. Fax: +86-551/559-1434, E-mail: ytpang@263.net 相似文献
69.
X. Hao J. Ma D. Zhang X. Xu Y. Yang H. Ma S. Ai 《Applied Physics A: Materials Science & Processing》2002,75(3):397-399
Transparent conducting antimony-doped tin oxide (SnO2:Sb) films were deposited on organic substrates by r.f. magnetron-sputtering. Polycrystalline films with a resistivity of
≈ 6.5×10-3 Ω cm, a carrier concentration of≈ 1.2×1020 cm-3 and a Hall mobility of ≈ 9.7 cm2 v-1 s-1 were obtained. The average transmittance of these films reached 85% in the wavelength range of the visible spectrum.
Received: 20 April 2001 / Accepted: 23 July 2001 / Published online: 17 October 2001 相似文献
70.
T. Gao G.W. Meng J. Zhang Y.W. Wang C.H. Liang J.C. Fan L.D. Zhang 《Applied Physics A: Materials Science & Processing》2001,73(2):251-254
Cu nanowire arrays have been synthesized using potentiostatic electrodeposition within the confined nanochannels of a porous
anodic alumina membrane. The Cu nanowire arrays and the individual nanowires have been characterized using SEM, TEM, SAED,
HREM and XRD. Investigation results reveal that the Cu nanowire arrays having high wire packing densities are highly ordered
over large areas. The individual Cu nanowires (diameter ∼60 nm) were single-crystal and found to be dense and continuous with
uniform diameters throughout their entire length. An optimum ECD condition (at lower overpotentials) for the synthesis of
single-crystal Cu nanowires was also discussed.
Received: 19 April 2001 / Accepted: 28 April 2001 / Published online: 20 June 2001 相似文献