Temperature dependence of the electron mobility in modulation-doped InGaAs/InAlAs single heterostructures has been investigated by Hall effect measurements in the temperature range from 15 K to 300 K in order to clarify the scattering mechanisms of the electrons. Two kinds of samples are used with doping densities in the InAlAs barrier layer, N D=3×1017 cm-3 and 1×1018 cm-3. The measured electron mobility is compared with the calculated values by taking into account the scattering by InAs-like and GaAs-like LO phonons in the InGaAs channel layer, in addition to the acoustic deformation potential, piezoelectric, ionized impurity, alloy disorder and interface roughness scatterings. The calculated electron mobility shows a good agreement with the experimental data when the alloy disorder potential is assumed to be about 0.7 eV.

“Sensitized thermal cells” do not rely on the Seebeck effect and do not require a temperature difference.

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An accelerator test facility, t-ACTS, established at Research Center for Electron Photon Science, Tohoku University, equips an injector consisted with a thermionic RF gun together with an energy filter and a 3 m traveling wave accelerating structure. A long-period undulator has been also installed for provide THz superradiance. Velocity bunching scheme proposed by Serafini and Ferrario is employed for ultra-short electron pulses production. A non-relativistic electron bunch, which is slightly slower than the velocity of light, is injected into the accelerating structure, and then the longitudinal phase space of the bunch is being rotated during acceleration. According to a numerical simulation, ~ 50 fs bunch can be produced by using the t-ACTS accelerator configuration. Proof-of-principle experiment of velocity bunching has been carried out by observing sub-picosecond electron pulse using a streak camera. We have succeeded in producing a sub-picosecond electron pulse in the t-ACTS. The details of the experiment for ultra-short electron pulse are described in this paper.

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Cytochrome c 3 , which has four bis-histidinyl coordinated hemes per molecule, is a redox protein, and stores electrons temporarily until recognizing a redox partner. This mechanism is called "electron pool effect". In this study, highly sensitive EQCM measurement clarified which heme in cytochrome c 3 caused the electron pool effect. To investigate the key heme to the electron pool effect, cytochrome c 3 mutants in which the sixth axial ligand of one heme was changed were prepared, and the intermolecular electron transfer was measured by viologen-immobilized electrode. The kinetics of the electron transfer complex formation between cytochrome c 3 and immobilized viologen indicated that redox of the heme II in cytochrome c 3 caused the electron pool effect.

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