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排序方式: 共有8307条查询结果,搜索用时 22 毫秒
961.
WU Feng-Min LU Hang-Jun FANG Yun-Zhang HUANG Shi-Hua 《理论物理通讯》2008,50(7):231-236
A realistic kinetic Monte Carlo (KMC) simulation model with physical parameters is developed, which well reproduces the heteroepitaxial growth of multilayered Ni thin film on Cu(100) surfaces at room temperature. The effects of mass transport between interlayers and edge diffusion of atoms along the islands are included in the simulation model, and the surface roughness and the layer distribution versus total coverage are calculated. Speeially, the simulation model reveals the transition of growth mode with coverage and the difference between the Ni heteroepitaxy on Cu(100) and the Ni homoepitaxy on Ni(100). Through comparison of KMC simulation with the real scanning tunneling microscopy (STM) experiments, the Ehrlich-Schwoebel (ES) barrier Ees is estimated to be 0.18±0.02 eV for Ni/Cu(100) system while 0.28 eV for Ni/Ni(100). The simulation also shows that the growth mode depends strongly on the thickness of thin film and the surface temperature, and the critical thickness of growth mode transition is dependent on the growth condition such as surface temperature and deposition flux as well. 相似文献
962.
Good optical quality U3+-doped PbCl2 single crystals of the composition Pb0.99U0.01Cl2 have been obtained by the Bridgman-Stockbarger method. Luminescence spectra of the crystals were recorded in a wide spectral range at room and liquid nitrogen temperatures, and are discussed. Strong infrared emission was observed under 514 nm laser pumping to the 5f26d1 bands. The lifetimes of the emitting levels in the visible and near infrared region are given. 相似文献
963.
Yu.M. Azhniuk V.V. Lopushansky V.O. Yukhymchuk Ya.I. Studenyak 《Journal of Physics and Chemistry of Solids》2008,69(1):139-146
The effect of heat treatment parameters on the chemical composition and average size of CdS1−xSex nanocrystals obtained in borosilicate glass by diffusion-limited growth is studied by optical absorption and Raman scattering spectroscopy. An increase of selenium content from 0.75 to 0.83 in the nanocrystals with the heat treatment temperature and duration is observed. Three lowest-energy optical transitions in CdS1−xSex nanocrystals are assigned to corresponding electronic transitions based on the observed dependence of the confinement-related absorption maxima on the nanocrystal size. 相似文献
964.
Low-temperature preparation of anatase titania-coated magnetite 总被引:1,自引:0,他引:1
Jingjing Xu Yanhui Ao Degang Fu Chunwei Yuan 《Journal of Physics and Chemistry of Solids》2008,69(8):1980-1984
A composite photocatalyst with an anatase titania shell and a magnetite core was prepared in a novel way at low temperature (75 °C at most) by coating photoactive titanium dioxide onto a magnetic Fe3O4 core. The photocatalytic activity of the prepared photocatalyst was evaluated by the degradation of model contaminated water of phenol and compared to single-phase titania (either Degussa P25 or prepared titania without magnetic Fe3O4). The results showed that the photoactivity was slightly depressed. Then, a remarkable improvement in photoactivity was achieved by modifying the photocatalyst with a SiO2 layer between the Fe3O4 core and TiO2 shell. The repetitive using of the modified photocatalyst was also investigated, and experimental results illustrated that the photocatalytic-degraded ratio of phenol was still higher than 80% after six cycles. 相似文献
965.
Woong Lee Joonsuk Song Takafumi Yao Hongchan Lee Bonheun Koo 《Applied Surface Science》2008,254(23):7728-7732
We have studied the molecular beam epitaxy (MBE) of GaSb films on GaAs (0 0 1) substrates by using ZnTe as a new buffer layer. GaSb films were grown on two distinct ZnTe surfaces and the influence of surface chemical composition of ZnTe on the morphological and structural properties of GaSb films has been investigated. Initial 2-dimensional (2D) growth of GaSb films is obtained on Zn-terminated surface consequently smooth morphology and high crystal quality GaSb films are achieved. The thin GaSb film (0.4 μm) grown on Zn-terminated ZnTe surface reveals considerably narrow X-ray diffraction linewidth (113 arcsec) along with small residual strain, which strongly supports the availability of ZnTe buffer for the growth of high-quality GaSb film. 相似文献
966.
In situ monitoring of nucleation and evolution of Ge nanodots on faintly oxidized Si(1 1 1) surfaces
We have investigated the nucleation and evolution of germanium (Ge) nanodot (ND)s taking place while depositing Ge onto the silicon (Si) (1 1 1) surfaces with ultra-thin Si oxide films by using ultra-high vacuum in situ high-resolution transmission electron microscopy in the profile-imaging geometry. Various types of growth phenomena such as nucleation, growth and coalescence of Ge NDs have successfully been observed. The results show that the growth phenomena of the Ge NDs are dramatically rapid after their size reaches the size of the critical nucleus. The critical nucleus size estimated from a model using the cohesive energy of the Ge NDs has been consistent with observed one. 相似文献
967.
M.L. Gomez-Herrera P. Rodriguez-Fragoso J.G. Mendoza-Alvarez 《Applied Surface Science》2008,255(3):761-763
In this paper we present results on the characterization of Zn-doped InGaAsSb epitaxial layers to be used in the development of stacked solar cells. Using the liquid phase epitaxy technique we have grown p-type InGaAsSb layers, using Zn as the dopant, and n-type Te-doped GaSb wafers as substrates. A series of Zn-doped InGaAsSb samples were prepared by changing the amount of Zn in the melt in the range: 0.1-0.9 mg to obtain different p-type doping levels, and consequently, different p-n region characteristics. Low temperature photoluminescence spectra (PL) were measured at 15 K using at various excitation powers in the range 80-160 mW. PL spectra show the presence of an exciton-related band emission around 0.642 eV and a band at 0.633 eV which we have related to radiative emission involving Zn-acceptors. Using the photoacoustic technique we measured the interface recombination velocities related to the interface crystalline quality, showing that the layer-substrate interface quality degrades as the Zn concentration in the layers increases. 相似文献
968.
969.
M. Willander Q.X. Zhao Q.-H. Hu P. Klason V. Kuzmin S.M. Al-Hilli O. Nur Y.E. Lozovik 《Superlattices and Microstructures》2008
In this paper we will give an overview of the status of catalytic growth and of low-temperature chemical growth of ZnO nanostructures performed in our laboratory. Particularly results employing different substrates will be discussed. The second part deals with structural and optical properties of ZnO nanorods. The results from high resolution transmission electron microscope (HRTEM), scanning electron microscope (SEM), photoluminescence (PL), Cathodoluminescence (CL), and Electroluminescence (EL), on single nanowires will be shown. Our results on surface morphology, bulk and the position of the catalyst as well as the optical properties including UV emission, lasing and white emission will all be presented and discussed. In the third part experimental results from electroluminescence of ZnO nanorods on different substrates in the UV in addition to excellent white light emission obtained from samples grown at low temperature are to be given and discussed. Finally the sensing of molecules in water by ZnO nanorods will be discussed from a theoretical point of view. Also fundamental properties of polaritons and excitons in ZnO nanostructures are to be highlighted. 相似文献
970.
以扩散理论为基础,建立以“基本微观过程” 为核心的新模型,引入交换比的概念,对存在表面活化剂时薄膜生长的微观过程进行Kinetic Monte Carlo模拟.模拟发现,活化层原子和沉积原子都会发生跨层间的扩散,跨层扩散主要是单个原子的扩散,层间扩散的原子数目随着温度的升高或沉积厚度的增加而增多.RLA模型中的“交换作用”只是若干个“基本微观过程”的组合,大多数交换不是位置的“完全交换”,交换比也并非恒为1.
关键词:
扩散理论
薄膜生长
交换作用
RLA 相似文献