電界放射現象は単吸着子に対する感度を持ち,フェムト秒台で連続的時間分解を行うに十分な電流量(＞10μA～6×1013e-/s)を単一原子から放出する。フェムトセコンドフィールドエミッションカメラ(Femtosecond Field Emission Camera, FFEC)は電界放射線を電気パルスで走査し時間分解することにより,単吸着子の超高速ダイナミックスを解明できる装置である。タングステンチップ上でのセシウム原子の拡散と銅フタロシアニン分子の振動測定について紹介する。また,電気パルスにより吸着子の運動を制御するメモリー素子への応用例も紹介する。
The atomic structure of monolayer graphite formed on a Ni (111) surface was investigated by means of LEED intensity analysis. We measured the I-V curves of the (1, 0), (0, 1) and (1, 1) diffraction spots from a 1×1 atomic structure, and analyzed them by using the Van Hove's analytical program based on dynamical theory. Three different atomic structures meeting the experimental requirement of the 3-m symmetry were evaluated with Pendry's reliability factor. The final best-fit structure characterized by the minimum Pendry's reliability factor of 0.22 is as follows; one carbon atom in a unit cell of the graphite overlayer is located at the on-top site of the topmost Ni atoms, while another carbon atom exists at the fcc-hollow site. The spacing between the flat overlayer and the topmost Ni layer is 2.11 ± 0.07 Å, which is much narrower than the interlayer spacing in bulk graphite (3.35 Å).
Naphthalene-2, 6-, -1, 5- and -2, 7-disulfonates (abbreviated as N26DS, N15DS and N27DS, respectively, and collectively abbreviated as NijDS) are intercalated individually in the interlayer region of Zn and Al layered double-hydroxides (Zn/Al-LDH). The intercalated products are prepared by means of mixing one of the organic isomers and 500°C-calcined carbonateintercalated Zn/Al-LDH under weak alkaline conditions. When N26DS or N15DS is used as an intercalated guest, two solid phases with basal spacings, 15 Å and 17 Å, abbreviated as 15 Å and 17 Å phases, respectively, are observed in powder X-ray diffraction (XRD) patterns. In contrast, only the 17 Å phase appears when N27DS is intercalated. The different basal spacings result from alternative orientations of NijDS (ij = 26 and 15) in the interlayer. The 15 Å phase appears exclusively in XRD patterns although the 17 Å phase is produced together with a by-product. NijDS (if =15 and 26) is more closely packed in the interlayer of the latter phase. The solid state chemistry has been investigated by using UV-visible diffuse reflection (DR) spectroscopy, differential thermal analysis/thermogravimetry (DTA/TG) and X-ray photoelectron spectroscopy (XPS).
We have conducted Auger depth profiling analyses of InP/GaInAsP multilayer specimens, in which the surface roughness was caused by the argon ion sputtering. We have, then, carried out the quantitative evaluation of the surface roughness using the distribution of the each pixel height taken by an atomic force microscope. The obtained histograms of surface roughness were used to calculate the resolution function together with the functions of electron escape depth and atomic mixing (Hofmann's MRI model). We also compared the resulting resolution function with the one obtained by the depth profiles measured. In this convolution calculation, we have assumed that the atomic mixing layer thickness was 2 nm and the information depth was 0.75 nm. The resulting resolution function was in excellent agreement with the one obtained from Auger depth profile. Therefore, we conclude that the distribution of the height of each pixel taken by AFM corresponds to the functions of surface roughness of the depth resolution function on the AES depth profile with sample cooling method.