We have studied the impact of GeH 4 pre-exposure of the hydroxyl-terminated SiO 2 surface on the silicon nucleation density in the early stages of low pressure chemical vapor deposition (LPCVD) using disilane (Si 2 H 6 ) so as to achieve higher areal density and better size uniformity in self-assembling formation of Si quantum dots (Si-QDs) on SiO 2 . Topographic images after the Si-QDs formation confirm that the dot density is as high as ~1.2×10 13 cm -2 on the GeH 4 -exposed SiO 2 , but in contrast ~3×10 11 cm -2 on HF-last SiO 2 . Notice that such a significant increase in the dot density results in a decrease in the dot size and improvement in the size uniformity. The result implies that the GeH 4 molecules react with surface OH bonds to generate nucleation sites efficiently for subsequent Si 2 H 6 -LPCVD. We also conformed that the dot density was controlled in the range of 4×10 9 to 1.3×10 13 cm -2 by changing the pressure and the substrate temperature in the GeH 4 -exposure pretreatment.

High-density Co nanodots with an areal dot density as high as 2.6 ×1011 cm-2 were formed on thermally grown SiO2 by exposing a ∼1.2-nm-thick Co layer to a remote H2 plasma without external heating. Also, Co-silicide nanodots on SiO2 were fabricated by silicidation of pregrown Si nanocrystals on SiO2, in which self-assembling Si nanocrystals by low pressure chemical vapor deposition (LPCVD), ultrathin Co film formation, and remote H2 plasma treatment were conducted sequentially. Electrical separation among nanodots in each of the Co and Co-silicide samples was verified from the changes in surface potential after charge injection using an AFM/Kelvin probe technique. The surface potential changes due to electron charging to Co nanodots and discharging from Co-silicide nanodots occur at a tip bias of 0 V, which are attributed to the work function difference between Co nanodots and Co-silicide nanodots. From the observation by magnetic force microscopy, Co nanodots can be active elements for both spin and charge storage.

A new mechanism of superfast motion of resistive domains in anisotropic superconductors is suggested. For bicrystals or sandwiches of anisotropic superconducting materials, the superfast motion is shown to arise due to the additional Joule heating of the kink regions of a resistive domain by eddy currents associated with them. Conditions under which the resistive domain in an anisotropic superconductor moves with a velocity up to the Fermi velocity, ∼10 8 cm s −1 , are discussed. As a result of the superfast motion, generation of electric oscillations of high amplitude with frequencies up to 10 10 Hz can take place. † Temporary address:

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