Electron localization in CdS nanocrystals studied by time-resolved terahertz spectroscopy
Measurement and Monte-Carlo simulations of THz photoconductivity spectra of CdS nanocrystalline films revealed a strong coupling between adjacent nanocrystals. Investigation of ultrafast dynamics provides information about initial sub-picosecond carrier cooling and subsequent carrier recombination.
Charge transport and localization in nanocrystalline CdS films: A time-resolved terahertz spectroscopy study
Z. Mics,1 H. Němec,1 I. Rychetský,1 P. Kužel,1,* P. Formánek,2 P. Malý,3 and P. Němec3 1Institute of Physics, Academy of Sciences of the Czech Republic, Prague, CZ-182 21, Czech Republic 2Institut für Strukturphysik, Technische Universität Dresden, D-01062 Dresden, Germany 3Faculty of Mathematics and Physics, Charles University in Prague, Prague, CZ-121 16, Czech Republic (Received 11 March 2011; published 28 April 2011)
Microstructure of the solder-casting zone in bridges of dental gold alloys.
The composition and structure were studied in the cast and in the solder of bridges which had failed clinically. Both materials were gold alloys but with different contents of Pt, Ag and Zn. The metallographic investigation revealed defects mostly in the solder, situated in the subsurface layer. SEM studied of the fracture surface revealed large porosites and a structure of dense parallel lines--striations--, indicating that the material had failed from fatigue. The materials in the fractured bridges were identified by micro-probe measurements. It was stated that cast material and solder material used together, were of different composition.