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A systematic study of the kinetics of axial Ni silicidation of as-grown and oxidized Si nanowires (SiNWs) with different crystallographic orientations and core diameters ranging from ∼ 10 to 100 nm is presented. For temperatures between 300 and 440 °C the length of the total axial silicide intrusion varies with the square root of time, which provides clear evidence that the rate limiting step is diffusion of Ni through the growing silicide phase(s). A retardation of Ni-silicide formation for oxidized SiNWs is found, indicative of a stress induced lowering of the diffusion coefficients. Extrapolated growth constants indicate that the Ni flux through the silicided NW is dominated by surface diffusion, which is consistent with an inverse square root dependence of the silicide length on the NW diameter as observed for (111) orientated SiNWs. In situ TEM silicidation experiments show that NiSi(2) is the first forming phase for as-grown and oxidized SiNWs. The silicide-SiNW interface is thereby atomically abrupt and typically planar. Ni-rich silicide phases subsequently nucleate close to the Ni reservoir, which for as-grown SiNWs can lead to a complete channel break-off for prolonged silicidation due to significant volume expansion and morphological changes.

The non-relativistic energies of ls%p (n = 2, 3, 4 and 5 ) states for the lithium isoelectronic sequence from Li I to Ne VI11 are calculated using the full-core plus correlation method. Relativistic and mass polarization effects on the energy are evaluated using first order perturbation theory. The fine structures are determined from the expectation values of the spin-orbit and spin-other-orbit interaction operators in the Pauli-Breit approximation. The higher order relativistic effects are estimated using the hydrogenic solution to the Dirac equation with an effective nuclear charge. The QED correction is also included. Our results are compared with the experimental and theoretical data in the literature. The fine structure results agree well with experiment. For ls%p energies with n 2 3, it appears that our results are quite accurate for all Z investigated. However, for the ls22p systems, the discrepancy with experiment grows monotonically from 0.5cm-' for Li I to 29cm-' for Ne VIII. This is very different from all the other ls'nl systems we have investigated using the same method. What separates ls22p apart from the others is the unusually large orbit-orbit interaction and mass polarization effects. For Z > 6, the expectation values of these perturbation operators are opposite in sign to those of the 1s' core. This energy increases quickly with Z.

The fabrication procedures of 3D ZnO/Au/CdS are schematically illustrated in Figure 1 , which can be divided into four steps, i.e., i) self-assembly mutilayers of PS spheres opals onto FTO substrates as a template, ii) ALD infi ltration of ZnO and removal of the PS spheres by calcination to obtain the 3D ZnO inverse opals, iii) decoration of Au nanoparticles on ZnO inverse opals, and iv) sensitization of CdS quantum dots on ZnO/Au inverse opals by a successive ion layer absorption and reaction (SILAR) route. The typical SEM images of ZnO inverse opals are displayed in Figure 2 a,b, where 3D periodically ordered structures and continuous voids are clearly observed. The diameter of the cavity size is ≈300 nm, which is slightly smaller than that of the PS spheres template. The typical thickness of the ZnO inverse opals is ≈3 µm, which can be determined from the cross-sectional SEM view (see Figure S1, Supporting Information). The SEM images of PS sphere opals and ZnO infi ltrated opals are provided in Figure S2, Supporting Information. shows Au/CdS cosensitization. The Au nanoparticles and CdS quantum dots layer are uniformly distributed on the surface without any pores clogging, keeping the periodical characteristic very well. The energy dispersive X-ray spectrometer (EDS) spectrum in Figure S3 of the Supporting Information collected Photoelectrochemical water splitting (PEC) represents a promising way to convert solar energy into hydrogen fuels. [1][2][3] The power conversion effi ciency is mainly affected by four aspects: i.e., light absorption, charge separation, charge migration, and charge recombination processes. [ 4 ] As such, an ideal photoelectrode should process high specifi c area, excellent charge migration, and light harvesting ability. In the past few years, great effort has been devoted to design novel electrodes with tailored nanostructures in order to boost the effi ciency. [5][6][7][8][9][10] For instance, 1D nanowires, [ 11,12 ] and nanotubes, [ 13 ] 3D branched nanowires [14][15][16][17] as well as 3D inverse opal [15][16][17][18][19] photoelectrodes have been explored. In particular, inverse opal structures with 3D continuous voids and unique abilities to localize light are more attractive for PEC applications. [ 20,21 ] Among the semiconductor materials, ZnO with a wide bandgap (3.37 eV) has been well-investigated as a photo anode due to its good photoactivity, high electron mobility, nontoxicity, and relatively low cost. [22][23][24] However, the poor light harvesting ability of ZnO in visible light wavelength greatly limits the overall effi ciency. To tackle this obstacle, several strategies have been developed, such as doping [ 25 ] and coupling with narrow band gap semiconductors such as CdS and/or CdSe. [26][27][28][29] Recently, the incorporation of plasmonic metal nanostructures has offered another new opportunity to improve the solar-to-hydrogen conversion efficiency by extending the light absorption wavelength as well as plasmonic energy transferring from the metal to the semiconducto...

By using a restricted variation method, the nonrelativistic energies of the lithiumlike ls22p systems are calculated. For lithium, the predicted nonrelativistic energy is -7.410 157 8( 9) a.u. [Pipin and Bishop, Phys. Rev. A45, 2736 (1992)l. The results for systems with Z = 4-10 also give significant improvement over the recent results of Wang et al., Physica Scripta 47, 65 (1993). These results show that this restricted variation method could be very useful for high precision variation calculations.