排序方式: 共有25条查询结果,搜索用时 15 毫秒
1.
Timothy David Atkinson 《Solid State Communications》2006,139(5):215-217
The electronic band gap of SrSe, in the CsCl-stuctured phase, was measured to 42 GPa via optical absorption studies. The indirect electronic band gap was found to close monotonically with pressure for the range of pressures studied. The change in band gap with respect to pressure, dEgap/dP, was determined to be −6.1(5)×10−3 eV/GPa. By extrapolation of our line fit, we estimate band gap closure to occur at 180(20) GPa. 相似文献
2.
We report spectroscopic ellipsometry studies in the energy range of 0.5-5 eV on samples of 1-10 bilayers of polymer and HgTe nanocrystals, which exhibit strong transitions at higher critical points in the dispersion relation. We show that the dispersion relation for nanocrystals can be modelled with the same concepts for critical points as used in semiconductor bulk optics. We find an energy shift of up to 0.4 eV of the critical points to higher energies compared to the HgTe bulk properties, caused by quantum confinement in the nanocrystals, which increases with decreasing nanocrystal size. 相似文献
3.
M. Zhou Y.K. Zhang L. Cai J.Z. Zhou Z.H. Shen X.R. Zhang S.Y. Zhang 《Applied Physics A: Materials Science & Processing》2003,76(7):1113-1116
In this communication, we report a numerical model that predicts the mechanical deformations associated with the pulsed laser
irradiation of a film surface, based on thermal diffusion theory. The model is consequently advanced to produce a method for
evaluating film adhesion strength. The epicenter surface displacements within the irradiated fields have been measured using
a heterodyne interferometer. The comparison of the experimental data and the displacements calculated by the model shows good
agreement. By investigating the propagating acoustic modes under non-destructive and destructive modes, we reveal that, with
or without interface delamination, the phase structure of the longitudinal waves will be altered due to the change of reflection
mode at the interface. Applying shock dynamics theory, we evaluate the adhesion strength of the TiN/stainless interface. We
also indicate the strain rate can be up to 105∼106 s-1 during film interface delamination.
Received: 5 April 2002 / Accepted: 24 June 2002 / Published online: 26 February 2003
RID="*"
ID="*"Corresponding author. Fax: +86-511/879-1919, E-mail: mzhou@ujs.edu.cn 相似文献
4.
S.A. Basun A.A. Kaplyanskii A.B. Kutsenko V. Dierolf T. Troester S.E. Kapphan K. Polgar 《Applied physics. B, Lasers and optics》2001,73(5-6):453-461
Low-temperature luminescence spectra of stoichiometric Cr:LiNbO3, congruent Cr:LiNbO3 and congruent Cr,Mg:LiNbO3 were studied. Dominant low-field and minor high-crystal-field optical centers are the Cr3+ impurity ions that preferentially occupy Li+ sites (CrLi) in the Cr:LiNbO3 crystals. Low-field centers related to Cr3+ substitution of Nb5+ (CrNb) occur in addition to CrLi in co-doped Cr,Mg:LiNbO3 samples. Application of high hydrostatic pressure leads to the transformation of dominant Cr3+ centers from low- to high-field type due to strong pressure-induced blue shift of the 4
T
2 state, resulting in its crossing with the 2
E state of Cr3+. This level-crossing effect was observed for the dominant Cr3+
Li and Cr3+
Nb centers at pressures that correlate well with estimations based on the 4
T
2-2
Eenergy gap (230 cm-1 and 1160 cm-1) and on the rate of their pressure-induced change (14.35 and 11.4 cm-1/kbar, respectively). We also studied inhomogeneous broadeningof the 2
E?4
A
2transitions at ambient pressure for the minor high-field “defect” Cr3+
Li centers in congruent LiNbO3. A fine structure in the spectral response of these centers was observed. The obtained results are discussed on the basis
of a microscopic hierarchic model for perturbed Cr3+ ions in the LiNbO3 lattice.
Received: 25 June 2001 / Published online: 2 November 2001 相似文献
5.
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
6.
Kazusato Shibata 《Solid State Communications》2006,139(10):501-505
Shock reactions between CX4 (X=Br or I) and NaN(CN)2 were investigated to prepare carbon nitrides. The post shock samples were characterized by the powder X-ray diffraction (XRD) technique. The XRD spectrum of the product showed a peak in the range of 0.324-0.336 nm in d-value corresponding to the (002) basal plane diffraction in graphitic structure. Elemental analysis (C, H, N, O) of the product showed that the atomic ratio of nitrogen to carbon (N/C) ranged from 0.38 to 1.3. Analysis of data revealed that the d-value increased and the nitrogen content decreased with the increase of the impact velocity. 相似文献
7.
8.
Inexpensive two-tip nanomanipulator for a SEM 总被引:1,自引:0,他引:1
One of the major obstacles for nanotechnology progress is the lack of effective tools and processes to build, characterize and manipulate nanosystems. Here, we present the development of a low-cost nanomanipulator with two probe tips that operates inside a scanning electron microscope. This manipulation system is based on parallel-guiding-plate-spring mechanism and inexpensive materials. The movements are divided on coarse and fine displacements, which are based on picomotors and piezoelectric elements, respectively. The nanomanipulator was applied to transport and manipulate nanotubes and semiconductor nanowires. The probe tips have independent electrical contacts, so that electrical two point measurements can be performed in situ. The system is expected to be a valuable tool for research laboratories working with nanostructures. 相似文献
9.
10.
We have succeeded in synthesizing two new lanthanum nitrides in a supercritical nitrogen fluid at high pressure (about 30 GPa) and high temperature (about 2000 K), using a diamond anvil cell and a YAG laser heating system. These nitrides were found to be stable down to 5 GPa and ∼300 K in a nitrogen atmosphere. One of the new lanthanum nitrides is a cubic P lattice-type phase, which is a main phase synthesized nitride. The calculated lattice parameter is at 5 GPa, 300 K. The other nitride is of a trigonal P lattice-type. The calculated lattice parameters are and at 5 GPa, 300 K. The most likely phase of the former new La nitride is , the structure of which may be similar to the Mn2O3-type (Ia80). The phase of the latter nitride is , the structure of which is the same as the La2O3-type (hP5). 相似文献