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本文报道了从粒子背散射堵塞效应的实验中所发现的单晶Si的{111}晶面粒子堵塞坑的新现象。单晶Si的{111}晶面有两个面间距d(111)(a)和d(111)(b),而{110}晶面只有一个面间距d(110)。由此导致两者的堵塞坑是不同的,我们已从α粒子和质子的Si单晶堵塞效应的实验得到了证实。并由此估计了d(111)(a)和d(111)(b)以及d(110)的2ψ1/2角。据作者了解,到目前为止,国内外还没有人发现此现象。此现象的发现对复杂晶体的堵塞和沟道效应的研究开阔了前景。
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氮是金刚石中最常见的杂质之一, 其对金刚石的缺陷发光具有重要的影响. 氮可以与金刚石中的本征缺陷形成复合缺陷. 本文首先利用阴极射线发光照片(CL)对一个高温高压合成的氮掺杂金刚石进行表征, 发现{100}晶面为蓝色, 然后利用透射电子显微镜(TEM)对该晶面进行电子辐照及后续退火处理, 以引入本征点缺陷进而形成含氮的复合缺陷, 并利用低温光致发光光谱(PL光谱)表征其缺陷发光特性, 发现该晶面主要以氮-空位复合缺陷(NV中心)发光为主, 并伴随着较弱的503 nm发光.
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金刚石
缺陷
发光 相似文献
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本文用俄歇电子能谱、X射线光电子能谱和紫外光电子能谱对用硫化铵溶液处理的InSb表面进行研究。结果表明,硫处理以后在样品表面生成。一层厚度约8?的硫化物钝化层,它对防止表面的氧化和碳沾污有明显的钝化作用。钝化层中,破原子既与锑原子成键,引起Sb3d芯能级发生1.9eV的化学位移;又与铟原子成键,引起In4d芯能级发生0.6—0.7eV的化学位移。350℃的真空退火使锑的硫化物发生分解。500℃退火没能使铟的硫化物完全分解,仍有一部分硫原子以铟的硫化物形式留在样品表面。
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Theγ-spektrum of Po212 (ThC′) has been measured by (γ, α)-coincidences with a fast-slow coincidence apparatus. The results are in excellent agreement with the conversion lines found by theLatyshev group. The absoluteγ-intensities have also been determined in order to get spins and parities of the levels by calculating the absolute conversion coefficients. Theβ-intensity leading to the exited states of Po212(ThC′) is estimated to be about one third of that measured byBurde andRozner by (β, α)-coincidences. Threeγ-lines measured byChinaglia andDemichelis by (γ, α)-coincidences do not agree with our results. The 2+ assignment of the first exited state is now well established, but for the other levels in the decay scheme there is still some uncertainty concerning spin and level assignment. 相似文献
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C. G. Lindén 《Zeitschrift für Physik A Hadrons and Nuclei》1977,280(1):51-60
A new, 480 ms, 29/2? isomeric level has been found in203Pb at an excitation energy of 2950.1 keV by bombarding204Hg with α-particles in the energy range 45–55 MeV using the Stockholm 225-cm cyclotron. This 29/2? state is suggested to be mainly due to the configuration (p 1 2/?2 f 5 2/?1 i 13 2/?2 )12. The 29/2? state decays predominantly by a 153.4 keV M2 transition to a 23/2? level and by a 1027.5 keV M4 transition to a 21/2+ level, followed by two E2 transitions of energies 258.6 keV and 838.7 keV, respectively, to the previously known 13/2+, 6.4 s isomeric level. The decay scheme of the 29/2? isomeric state is based on experimental information obtained from total and delayedγ-ray intensities,γγ-coincidences, excitation functions, lifetime and delayed conversion electron measurements. The presence of the 29/2? level confirms an essential and expected feature of the shell model for five neutron holes added to the208Pb-core. 相似文献
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Vibrational spectrum of the ordered Pt(111)–( ?3 ×?3 ) \left( {\sqrt {3} \times \sqrt {3} } \right)
R30°–K surface superstructure formed on the platinum surface with adsorption of 1/3 ML potassium is calculated with the use of the
interatomic interaction potentials obtained in the strong bond approximation. Relaxation of the surface, dispersion of the
surface phonons, local density of vibrational states, and polarization of phonon modes of adatoms and atoms of the substrate
are discussed in the work. The theoretical results obtained agree well with the available experimental data. 相似文献
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Role of the Λ(1600) is studied in the ${K}^{-}p\to {\rm{\Lambda }}{\pi }^{0}{\pi }^{0}$ reaction by using the effective Lagrangian approach near the threshold. We perform a calculation for the total and differential cross sections by considering the contributions from the Λ(1600) and Λ(1670) intermediate resonances decaying into ${\pi }^{0}{{\rm{\Sigma }}}^{* 0}(1385)$ with ${{\rm{\Sigma }}}^{* 0}(1385)$ decaying into ${\pi }^{0}{\rm{\Lambda }}$. Additionally, the non-resonance process from u-channel nucleon pole is also taken into account. With our model parameters, the current experimental data on the total cross sections of the ${K}^{-}p\to {\rm{\Lambda }}{\pi }^{0}{\pi }^{0}$ reaction can be well reproduced. It is shown that we really need the contribution from the Λ(1600) with spin-parity ${J}^{P}=1/{2}^{+}$, and that these measurements can be used to determine some of the properties of the Λ(1600) resonance. Furthermore, we also plot the π0Λ invariant mass distributions which could be tested by the future experimental measurements. 相似文献
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用分子动力学模拟的方法和Tersoff多体势函数对以一定能量入射的C 60在石墨(0001)表面以及硅(111)表面碰撞的过程进行模拟研究.结果发现:碰撞过程是高度非弹性的,在弹回过程中,C60分子质心的运动可被看作是在准谐势下的运动 .C60以240 eV初始能量入射到石墨表面时,C60分子有严重的扭曲,最终将平铺在石墨表面形成薄膜;C60分子以30 eV初始动能入射到石墨表面时,将保持完好球形沉积在石墨表面;C60分子以60 eV的初始动能碰撞硅(111)表面时,C60分子最终沉积在硅表面,碰撞过程中C60分子有形变. 相似文献
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Junfeng Sun Yueling Yang Na Wang Qin Chang Gongru Lu 《International Journal of Theoretical Physics》2017,56(6):1892-1902
The ψ(4040) and ψ(4160) →\(D_{d}^{\pm }D_{s}^{\mp }\) decays are studied with the perturbative QCD approach phenomenologically. It is found that branching ratios for these decays are insensitive to the S-D mixing angle ?? ∈ [?30°,30°], and too tiny to be measured in the near future experiments. 相似文献
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《Surface science》1989,217(3):L435-L440
A recent article [Surface Sci. 209 (1989) 379] has attempted to improve the agreement between our original X-ray diffraction data [Phys. Rev. Letters 54 (1985) 1275; Surface Sci. 186 (1987) 499] and the proposed distorted vacancy model by the introduction of an additional, partially occupied atom in the unit cell. Here we show that almost as much improvement can be obtained by introducing second-layer displacements into the original structure. This raises questions of uniqueness in crystallographic structure determination and the level of detail attainable without overinterpretation of data. 相似文献
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M.A. Grishin H.S. Karlsson M. Månsson U.O. Karlsson 《Applied Physics A: Materials Science & Processing》2003,76(3):299-302
The conduction band electronic structure and the electron dynamics of the clean InSb(111)2×2 surface have been studied by
laser based pump-and-probe photoemission. The results are compared to earlier studies of the InSb(110) surface. It is found
that both the energy location and the time dependence of the photoexcited structures are very similar for the two surfaces.
This indicates that the dominant part of the photoemission signal in the conduction band region is due to excitations of electrons
in the bulk region and that the surface electronic states play a minor role. The fast decay of the excited state, τ∼12 ps,
indicates that diffusion of hot electrons into the bulk is an important mechanism.
Received: 9 May 2001 / Accepted: 9 July 2002 / Published online: 25 October 2002
RID="*"
ID="*"Corresponding author. Fax: +46-0824/913-1, E-mail: gm@matphys.kth.se 相似文献
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Kuang-Ta Chao 《Zeitschrift fur Physik C Particles and Fields》1981,7(4):317-320
The mass spectrum and decay modes of the \((cc) - (\overline {cc} )\) states are estimated in a quark-gluon model. We argue that the peculiar resonance-like structures ofR(e + e ? →hadrons) for \(\sqrt s = 6 - 7\) GeV may be due to production of theP-wave \((cc) - (\overline {cc} )\) states. They are predicted to lie in the range 6.4–6.8 GeV and mainly decay into charmend mesons. 相似文献