47 research outputs found
Thermal stability of titanium nitride for shallow junction solar cell contacts
To demonstrate the thermal stability of titanium nitride as a high-temperature diffusion barrier, the TiN-Ti-Ag metallization scheme has been tested on shallow-junction (~2000 Ă
) Si solar cells. Electrical measurements on reference samples with the Ti-Ag metallization scheme show serious degradation after a 600 °C, 10-min annealing. With the TiN-Ti-Ag scheme, no degradation of cell performance is observed after the same heat treatment if the TiN layer is >~1700 Ă
. The glass encapsulation of cells by electrostatic bonding requires such a heat treatment
Investigation of titanium-nitride layers for solar-cell contacts
Reactively sputtered titanium-nitride layers have been incorporated as diffusion barriers in a titanium-silver metallization scheme on silicon, Backscattering analysis (2-MeV He+, RBS) indicates that the integrity of the system is basically preserved during annealing at 600° for 10 min. Electrical properties were determined for titanium-nitride layers prepared under different deposition conditions. Resistivity and Hall mobility appear to depend on the oxygen contamination of the deposited material. For the lowest oxygen concentration (<5 at %) a resistivity of 170 ”Ω . cm has been found
Dust Destruction in the High-Velocity Shocks Driven by Supernovae in the Early Universe
We investigate the destruction of dust grains by sputtering in the
high-velocity interstellar shocks driven by supernovae (SNe) in the early
universe to reveal the dependence of the time-scale of dust destruction on the
gas density in the interstellar medium (ISM) as well as on the
progenitor mass and explosion energy of SN. The
sputtering yields for the combinations of dust and ion species of interest to
us are evaluated by applying the so-called universal relation with a slight
modification. The dynamics of dust grains and their destruction by sputtering
in shock are calculated by taking into account the size distribution of each
dust species, together with the time evolution of temperature and density of
gas in spherically symmetric shocks. The results of calculations show that the
efficiency of dust destruction depends not only on the sputtering yield but
also on the initial size distribution of each grain species. The efficiency of
dust destruction increases with increasing and/or increasing
, but is almost independent of as long as is the same. The mass of gas swept up by shock is the increasing function
of and the decreasing function of . Combining
these results, we present the approximation formula for the time-scale of
destruction for each grain species in the early universe as a function of
and . This formula is applicable for investigating
the evolution of dust grains at the early epoch of the universe with the
metallicity of Z \la 10^{-3} . The effects of the cooling processes
of gas on the destruction of dust are briefly discussed.Comment: 49 pages including 7 tables and 25 figures, accepted for publication
in Ap
Altes und Neues ĂŒber die vegetarianische Lebensweise : Vortrag gelegentlich des veget. Vereinstages gehalten im BĂŒrgersaale des Rathhauses zu Berlin am 2. Juni 1880
von Alfred von Seefel
Der VR-Interaktions-Baukasten. Methoden der visuellen und haptischen Augmentierung zur multimodalen Interaktion Schlussbericht
Available from TIB Hannover: F04B1630 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung und Forschung (BMBF), Bonn (Germany)DEGerman