Carrier dynamics of electrons and holes in moderately doped silicon

A time-domain spectroscopic technique, based on the generation and detection of a collimated beam of subpicosecond broadband terahertz pulses, is used to measure the absorption and dispersion of n- and p-type silicon, with resistivities of 0.1, 1, and 10 Ohm-cm in the submillimeter range of 0.1-2 THz. From the transmission measurements performed at room temperature and at 80 K, the absorption and dispersion, and concomitantly the full complex conductivity, of the doped silicon could be obtained. The results provide an accurate view on the dynamics of the electrons and the holes. Although the simple Drude model, with an energy-independent relaxation time, gives a surprisingly accurate description of the observed carrier dynamics, the measurements do show that some refinements are needed. An extended model, with an energy-dependent carrier-relaxation rate, can explain most of the observed deviations from the simple Drude model.Peer reviewedElectrical and Computer Engineerin

Electrochemical promotion of ruthenium oxide catalysts for the gas phase combustion of ethylene

The electrochem. promotion of RuO2 catalyst films, deposed onto yttria stabilized zirconia solid electrolyte (YSZ), was studied for the gas phase combustion of ethylene. Two order of magnitude increase in the reaction rate was obtained during anodic polarization of the catalyst compared with the unpromoted rate under open circuit conditions. The rate increase was about three orders of magnitude higher than the rate of oxygen pumping to the catalyst. Work function measurements were used for the study of the interaction of the RuO2/YSZ interface and the RuO2/gas interface. A two step mechanism was obsd. for the electrochem. promotion. A 1st fast modification is due to the polarization of the RuO2/YSZ interface and a slower modification due to the backspillover of oxygen ions from the three phase boundary over the gas exposed catalyst surface. [on SciFinder (R)

Electrochemistry in micellar media. Dimerization of electroreducible amphiphilic aromatic ketones in aqueous media: a stereochemical approach

International audienc