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本文在流动余辉装置上,研究了亚稳态He(2^3S)原子与C2H3CN分子碰撞传能,观察到了激发态产物CN(A,B)、CH(A)H的发射光谱。 相似文献
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在流动余辉装置上,我们研究了亚稳态原子Ne(^3P0,2)与乙腈的能量转移反应,观察到了CN(A-X),CN(B-X),CH(A-X)的发射谱。计算了CN(A,B)的相对振动粒子数布居,并对该反的机理进行了讨论。 相似文献
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复合物p—C6H4F2...NH3(ND3)外部振动的共振双光子电离光谱 总被引:1,自引:0,他引:1
利用共振光电离技术和飞行时间质谱技术,观察到了复合物p-C6H4F2...NH3(ND3)的共振双光子电离光谱。光谱分析表明,复合物分子间的伸 振动频率为86.4cm^-1;由复合物光解离机理以及伸缩模的失谐参数与键有的关系。获得了复合物电子激发态S1和基态S0的键能信息。Abinitio计算表明,p-C6H4F2...NH3(ND)复合物的几何结构是:NH3分子中的N原子位于垂直p-C6H4F2 相似文献
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NEC研究先进的Al┐Ge┐Cu工艺据SemicondIntl1996年第6期报道:NEC公司的研究人员正在不断观察Ge加入Al-Cu互连后的作用,以得到一种有实际生产价值的低温回流溅射工艺。这种使用低温回流溅射和化学机械抛光金属平坦化的Al-Ge... 相似文献
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采用自组装(SA)技术制备了对甲苯基硫脲、对氯苯基脲和2,4,6-三溴苯基硫脲Au表面的自装单分子膜(SAMs)。在Au-溶液界面,硫脲S原子与Au-S键诱导吸附分子形成取向在序排列的单分子膜。用原子力显微镜(AFM)对单分子膜进行了直接观察,AFM所获得的结构信息与椭圆偏振测量、接触角测量和X-射线光电子能谱(XPS)分析结果一致。 相似文献
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在焊点与铜基之间形成的Cu-Sn合金成分对表面安装器件的疲劳寿命起着关键性的作用。本文着重研究了93.5Sn3.5Ag(简写为Sn-Ag)焊料与Cu基界面间形成的合金层,通过电子扫描显微镜(SEM),X衍射(XDA)及能谱X射线(EDX)等分析发现,在Sn-Ag与Cu基界面上存在Cu6Sn5及Cu3Sn两种合金成分,且随着热处理时间增加,Cu6Sn5合金层增厚,并在该处容易出现裂纹而导致焊点强度减弱,从而使焊点产生疲劳失效。 相似文献
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Photoluminescence (PL) of n-type GaAs:Te:Cu and GaAs:Sn:Cu with an electron density of about 1018 cm?3 was studied at 77 K. A broad band with a peak at the photon energy near 1.30 eV (GaAs:Te:Cu) or 1.27 eV (GaAs:Sn:Cu) was dominant in the PL spectrum under interband excitation. This band arose from the recombination of electrons with holes trapped by CuGaTeAs or CuGaSnGa complexes. It has been found that the low-energy edge of the excitation spectrum of this PL band at photon energies below ~1.4 eV is controlled by the optical ejection of electrons from a complex into the conduction band or to a shallow excited state. The PL polarization factors upon excitation by polarized light from this spectral range suggest that the complexes have no additional distortions caused by an interaction of a hole bound at the center in the light-emitting state with local phonons of low symmetry. This feature makes CuGaTeAs and CuGaSnGa complexes different from those with the Ga vacancy (V Ga) instead of CuGa. The dissimilarity arises from the difference in the intensity of interaction of a hole localized at the orbital of an isolated deep-level acceptor in the state corresponding to its preemission state in the complex (Cu Ga ? and V Ga 2? ) with low-symmetry vibrations of atoms. The perturbation of the hole orbital induced by the donor in the complex practically does not affect this interaction. 相似文献
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《Materials Science in Semiconductor Processing》2000,3(1-2):123-127
The atomistic simulations in the framework of the Generalized Simulated Annealing approach (GSA) and classical force fields lead to very reasonable relaxed geometries around the carbon interstitial in O-, T-, and TS-sites. We have thus shown that a highly efficient energy-sampling and relaxation scheme, implemented with tight constraints on a limited volume, provides a powerful steering mechanism for selection of geometries suitable for detailed investigation by first-principles methods. The results, based upon harmonic interactions between Cu atoms and a van der Waals interaction between Cu and C, predict the relaxed O-site to be more stable than the T-site by ∼1.2 eV, in accordance with general expectations. The TS barrier to OO diffusion is found to be ∼0.8 eV, at a temperature of 0 K; the TS exhibits a strong local axial distortion of the pseudo-octahedral environment. The Density Functional results indicate a charge transfer of ∼1 e to carbon, mostly from the first neighbor shell, in all relaxed environments studied. Bond-order data show the Cu–C interaction to be bonding in nature, despite the net ‘repulsive interaction’ leading to a surface state of lower net energy. 相似文献
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Qisheng Zhang Takeshi Komino Shuping Huang Shigeyuki Matsunami Kenichi Goushi Chihaya Adachi 《Advanced functional materials》2012,22(11):2327-2336
The temperature dependence of luminescence from [Cu(dnbp)(DPEPhos)]BF4 (dnbp = 2,9‐di‐n‐butylphenanthroline, DPEPhos = bis[2‐(diphenylphosphino)phenyl]ether) in a poly(methyl methacrylate) (PMMA) film indicates the presence of long‐life green emission arising from two thermally equilibrated charge transfer (CT) excited states and one non‐equilibrated triplet ligand center (3LC) excited state. At room temperature, the lower triplet CT state is found to be the predominantly populated excited state, and the zero‐zero energy of this state is found to be 2.72 eV from the onset of its emission at 80 K. The tunable emission maximum of [Cu(dnbp)(DPEPhos)]BF4 in various hosts with different triplet energies is explained in terms of the multiple triplet energy levels of this complex in amorphous films. Using the high triplet energy charge transport material as a host and an exciton‐blocking layer (EBL), a [Cu(dnbp)(DPEPhos)]BF4 based organic light‐emitting diode (OLED) achieves a high external quantum efficiency (EQE) of 15.0%, which is comparable to values for similar devices based on Ir(ppy)3 and FIrpic. The photoluminescence (PL) and electroluminescence (EL) performance of green emissive [Cu(μI)dppb]2 (dppb = 1,2‐bis[diphenylphosphino]benzene) in organic semiconductor films confirmed its 3CT state with a zero‐zero energy of 2.76 eV as the predominant population excited state. 相似文献
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Jiale Feng Antti-Pekka M. Reponen Alexander S. Romanov Mikko Linnolahti Manfred Bochmann Neil C. Greenham Thomas Penfold Dan Credgington 《Advanced functional materials》2021,31(1):2005438
The effect of the heavy metal atom on the photophysics of carbene-metal-amide (CMA) photoemitters is explored, where the metal bridge is either Au, Ag, or Cu. Spectroscopic investigations reveal the coupling mechanism responsible for communication between the singlet and triplet manifolds. The photophysical properties do not reflect expected trends based upon the heavy atom effect, as both direct coupling between charge-transfer states and spin-vibronic coupling via a ligand-centered triplet state are present. Direct coupling is weakest for CMA(Ag), increasing the importance of the spin-vibronic pathway and rendering its properties more sensitive to inter-state energy gaps than for the Au and Cu-bridged analogues. The measured activation energy correlates with the expected exchange energy of the charge-transfer state, which is also closely related to the length of the bonds joining the carbene and amide ligands, and decreases in the order CMA(Cu) > CMA(Au) > CMA(Ag). These findings reveal that reducing interference between charge-transfer and ligand-centers excited, and minimizing exchange energy, are required for developing efficient luminescent CMA complexes. 相似文献
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激光频率对DNA分子混沌态影响的研究 总被引:11,自引:3,他引:8
通过对激光与DNA作用的运动方程迭代求解和关联维计算,讨论了不同激光频率对DNA分子系统混沌行为的影响,并对较大的激光频率范围内均能引起生物的遗传变异现象进行了解释。 相似文献
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V. S. Bagaev V. V. Zaitsev Yu. V. Klevkov V. S. Krivobok E. E. Onishchenko 《Semiconductors》2003,37(3):283-287
The photoluminescence from high-purity polycrystalline ZnTe has been studied. The evolution of the emission spectra upon annealing in Zn is analyzed. The effect of impurity aggregation is observed in the initial samples. This effect gives rise to an undulatory spectrum on the long-wavelength wing of the line associated with emission from an acceptor-bound exciton. It is demonstrated that annealing leads to homogenization of the impurity distribution, which results in the appearance of a rich structure of two-hole transitions. An analysis of these lines yields the energies of the ground and excited states of Li and Cu acceptor impurities. 相似文献
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Lina Su Pengfei Wang Junhui Wang Dongpeng Zhang Haitao Wang Yi Li Sihui Zhan Jinlong Gong 《Advanced functional materials》2021,31(47):2104343
Single-atom photocatalysts have shown their fascinating strengths in enhancing charge transfer dynamics; however, rationally designing coordination sites by metal doping to stabilize isolated atoms is still challenging. Here, a one-unit-cell ZnIn2S4 (ZIS) nanosheet with abundant Cu dopants serving as the suitable support to achieve a single atom Pt catalyst (Pt1/Cu–ZIS) is reported, and hence the metal single atom–metal dopant interaction at an atomic level is disclosed. Experimental results and density functional theory calculations highlight the unique stabilizing effect (Pt–Cu interaction) of single Pt atoms in Cu-doped ZIS, while apparent Pt clusters are observed in pristine ZIS. Specifically, Pt–Cu interaction provides an extra coordination site except three S sites on the surface, which induces a higher diffusion barrier and makes the single atom more stable on the surface. Apart from stabilizing Pt single atoms, Pt–Cu interaction also serves as the efficient channel to transfer electrons from Cu trap states to Pt active sites, thereby enhancing the charge separation and transfer efficiency. Remarkably, the Pt1/Cu–ZIS exhibits a superb activity, giving a photocatalytic hydrogen evolution rate of 5.02 mmol g−1 h−1, nearly 49 times higher than that of pristine ZIS. 相似文献
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Kanglin Xiong Sung Hyun Park Jie Song Ge Yuan Danti Chen Benjamin Leung Jung Han 《Advanced functional materials》2014,24(41):6503-6508
Large‐area, free‐standing and single‐crystalline GaN nanomembranes are prepared by electrochemical etching from epitaxial layers. As‐prepared nanomembranes are highly resistive but can become electronically active upon optical excitation, with an excellent electron mobility. The interaction of excited carriers with surface states is investigated by intensity‐dependent photoconductivity gain and temperature‐dependent photocurrent decay. Normally off enhancement‐type GaN nanomembrane MOS transistors are demonstrated, suggesting that GaN could be used in flexible electronics for high power and high frequency applications. 相似文献
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采用双坩埚嵌套高温固相法在950℃下成功地合成了Ba2ZnS3∶Cu荧光粉,探讨了工艺条件和Cu掺杂量对样品发光亮度的影响,用X射线粉末衍射(XRD)、扫描电子显微镜(SEM)和荧光分光光度计分别对其结构、形貌和发光性能进行了表征。结果表明:样品具有单一的Ba2ZnS3晶相结构;与Ba2ZnS3基质不同,该荧光粉的激发光谱在近紫外区存在一个从275~350nm的宽激发带,归因于Cu发光中心的吸收;该荧光粉在近紫外光激发下发出明亮的黄光,发射中心波长位于560nm处,是一种良好的黄光材料。 相似文献
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Wetting interaction between Sn-Zn-Ag solders and Cu 总被引:4,自引:0,他引:4
The wetting interaction of Sn-(7.1–9)Zn-(0–3)Ag solders with Cu was investigated from 230°C to 300°C. The wetting time, wetting
forces, and activation energy of the wetting reaction were studied. The wetting time decreases with increasing temperature
and increases with Ag content. The wetting force exhibits a disproportional correlation to temperature rise, while no trend
was observed with respect to Ag content. The wetting behavior was ascribed to the interaction between Cu and Zn. The AgZn3 compound was formed at the interface when the solder contains 0.3% Ag and above, while it was formed within the bulk solder
at 2% Ag and above. 相似文献