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As a step toward growth of HgCdTe on GaAs and GaAs/Si substrates, Cd1–yZnyTe buffer layers were grown on these substrates. A conventional pyrolytic process at relatively high temperature (441 °C) was used. Epitaxial growth on GaAs was achieved for all alloy compositions, 0≤y≤1. The solid–vapor distribution curve for alloy deposition was determined experimentally for one particular set of deposition parameters, and compared with a thermodynamic model. Deposit uniformity was also studied experimentally and compared with a model incorporating coupled fluid dynamics and mass transport (but not chemical kinetics) with realistic reactor boundary conditions and thermal effects. Epitaxial growth on the GaAs(123) substrates orientation was studied by x-ray techniques. Cd1–yZnyTe epitaxial layers grown on these substrates were tilted with respect to the substrate toward 〈111〉, about a 〈12̄1〉 axis. The degree of tilt depended on the alloy composition y, ranging from 1.7° for y=1 to 3.2° for y=0. These results are consistent with a model of the GaAs(123) surface as a terraced structure consisting of (111) oriented ledges and steps parallel to [12̄1]. The crystal lattice perfection of the epitaxial layers was assessed by x-ray double-crystal rocking curve analysis. The best full width at half-maximum (FWHM) obtained for CdTe layers was 80 arc s, and for ZnTe layers it was 150 arc s. Cd0.96Zn0.04Te layers also grown on GaAs/Si(001) tilted 3.5° toward 〈111〉. Some layers grown on these substrates also had rocking curve FWHM≤100 arc s. Hg0.7Cd0.3Te was grown by liquid phase epitaxy on a CdZnTe/GaAs/Si substrate, and the resulting layer had a rocking curve FWHM of 165 arc s.

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A new method for doping organic semiconductors is presented. The most common dopant for the widely used a-sexithiophene (a6T), FeC13, was co-sublimed with the oligothiophene under UHV-conditions. The solid-state doping effects were studied for systematically varied dopant concentrations in-situ with XPS, UPS, and HREELS. Up to a doping level of one effective charge per a6T the results can be interpreted as polaron formation. At higher dopant concentrations polaron bands are most probably formed.

Structures and stability ranges of the YBa2Cu3O7–x interface were studied with AES, SIMS, XPS, and TEM. For silicon substrates, the formation of Ba silicates can be detected which even at T = 550 K leads to reduced Tc values and non‐epitaxial growth of YBa2Cu3O7–x (YBCO). Yttria stabilized zirconia (YSZ) buffer layers between Si substrates and YBCO lead to epitaxial overlayer growth and improved superconducting properties whereas CaF2 is not suitable for this purpose.—Furthermore, SiO2, YSZ, and CaF2 were tested for their suitability as passivation layers against the influence of humidity. As‐passivated superconducting films are stable up to 500 K in 100% humid air. Above this temperature the superconductor is reduced chemically. Non‐passivated films, however, are stable only at temperatures below 450 K and are destroyed totally in humid air at higher temperatures.