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MgB2 thin films were deposited on SiC buffered Si substrates by sequential electron beam evaporation of a BMg bilayer followed by in situ annealing. The application of a SiC buffer layer enables the maximum annealing temperature of 830 °C to be reached. Transmission electron microscopy analysis confirms the growth of a nanogranular MgB2 film and the presence of a Mg2Si compound at the surface of the film. The 150200 nm thick films show a maximum zero resistance critical temperature TC0 above 37 K and a critical current density JC~106 A cm-2 at 11 K.
The Spray Ion Layer Gas Reaction (Spray-ILGAR) technique is a new variation on the ILGAR technique used to prepare chalcogenide thin films. High quality indium sulfide thin films were produced by Spray-ILGAR with an indirect bandgap of 2.2 eV and a high suitability for use as buffer layers in chalcopyrite solar cells. The process involves the cyclical spray deposition of an indium containing precursor layer followed by its conversion to sulfide using hydrogen sulfide gas. Analysis of the deposition reveals that the indium chloride based precursor is transported via the vapour phase from the spray droplets to the substrate surface.
The therapy of eye tumors with fast protons is an excellent tool giving very high local control rates. At the Helmholtz-Zentrum Berlin (HZB) almost 1800 patients were treated since 1998. A 2 MV Tandetron was installed as injector for the k = 132 HZB cyclotron. Using the standard 358 duoplasmatron ion source with direct extraction of negative hydrogen ions an extremely stable proton beam can be delivered, both on the short-term and the long-term scale. The hair-needle filaments made from thoriated tungsten wires have safe operation times of more than 1000 h.
The deposition of boron carbonitride layers
on silicon substrates by a microwave plasma enhanced
chemical vapour deposition (MW-PECVD) process using
N-trimethylborazine (TMB) and benzene as precursors
is presented. As plasma gases argon and nitrogen
were used. In this investigation we focus on the influence
of the gas composition, substrate temperature and
-bias on the layer composition, layer structure as well as
the thermal stability. The films were analyzed with respect
to their composition and bonding structure using
elastic recoil detection analysis (ERDA) and X-ray
photoelectron spectroscopy (XPS). Furthermore, nanoindentation
measurements before and after annealing
tests at 500 and 700°C were performed. The measurements
show a strong dependence of the structure and
mechanical properties on the substrate temperature.
The hydrogen content strongly decreases to 8 at.% with
higher substrate temperatures. Simultaneously, the layer
hardness and Youngs modulus increase up to 21 and
173 GPa, respectively. The hardness does not decrease
after annealing for 1 hour at 700°C.
The TOF-ERDA setup at the ISL Berlin was used to perform precise energy loss measurements of scattered ions. Different samples were irradiated with a 350 MeV Au beam and the TOF of the recoiled elements was measured without and with an additional metal stopping foil (Fe, Ag or Au) behind the target. The energy loss of the different elements in these foils was derived from the shift of the high energy edges of the spectra. The values are mainly consistent with the semi-empirical Ziegler/Biersack data. Deviations, trends and possible errors are discussed.
Ultra-thin In(OH)x Sy/Pb(OH)x Sy heterostructures were formed by the wet chemical SILAR (successive ion layer adsorption and reaction) technique. ERDA (elastic recoil detection analysis) was used for stoichiometry analysis. The heterocontacts were conditioned by joint annealing of the two layers at different low temperatures in air. The charge selectivity was demonstrated with various small area solar cell structures. The results are discussed on the base of formation of bonds between sulphide clusters and passivation of defects with hydrogen containing species in hydroxy-sulphides.