Potential-dependent surface structures of Au (111) and Au(100) single-crystal electrodes in a 50 mM H 2 SO 4 solution were investigated at an atomic level using in situ surface X-ray scattering (SXS) techniques. It was confirmed that both the Au(111) and Au(100) surfaces were reconstructed with an attached submonolayer of an oxygen species, most probably water, at 0 V (vs Ag/AgCl). Results at +0.95 V supported a previously suggested model for both the Au(111) and the Au(100) electrodes that, based on infrared and scanning tunneling microscopy measurements, the surfaces were a (1 × 1) structure with the coadsorbed sulfate anion and hydronium cation (H 3 O + ). At +1.05 V, where a small amount of an anodic current flowed, adsorption of a monolayer of oxygen species was observed on both surfaces. When the single-crystal gold electrodes were electrochemically oxidized at +1.40 V, the expansion of the gold surface by about one monolayer of Au atoms was observed, suggesting the penetration of oxygen into the surface gold layers (i.e., the formation of two layers of surface oxide). When the surface oxide was reduced at +0.65 V, the surface structure returned back to the structure observed at +0.95 V before the oxide formation (i.e., a (1 × 1) structure with coadsorbed sulfate anion and H 3 O + ). When the potential was reduced to 0 V, the surfaces were reconstructed again but with slightly more random structures than those before the potential cycle.

A channel length of a c-axis aligned crystal indium gallium zinc oxide (CAAC-IGZO) transistor having low off-state current at a yA/µm level was decreased to 100 nm, and the electrical characteristics and short-channel effect of the CAAC-IGZO transistor were researched. As a result, we found that, in the CAAC-IGZO transistor with L = 100 nm, even with a gate insulator film having an equivalent oxide thickness (EOT) = 11 nm, an extremely small off-state current of 380 yA/µm at 85 °C is maintained, in addition channel length dependence of the electrical characteristics is hardly seen. Favorable values of characteristics of the CAAC-IGZO transistor can be obtained, such as subthreshold slope (SS) = 77 mV/dec, drain induced barrier lowering (DIBL) = 73 mV/V, threshold voltage (V th) = 0.65 V, and on-state current (I on) = 65 µA/µm. These results suggest the possibility that the CAAC-IGZO transistor can be applied to an LSI in a deep submicron region.