The interface between ZnO/Si and ZnO/Si02 was studied by etching through the junction region and analysing XPS and Auger LMM spectra. By comparing XPS shifts and peak splitting in the Si2p spectra, chemical complexes of the form Si-0,-Zn ( x = l ) were identified at the ZnO/Si interface. The transition from ZnO/SiO, was characterized by intensity variations in the 0 1 s spectra. Relative to metallic zinc the Auger LMM shifts were -4 eV for ZnO on Si and -3 eV for ZnO on SiOz. Such shifts were attributed mainly to extra-atomic relaxation. Correspondence of levels (zero Auger shifts) was observed in the spectra from the two interface regions suggesting that zinc extra-atomic relaxation was constant throughout a region of varying chemical composition.

The paraconductivity of a number of c-axis-oriented YBa2Cu3Ox thin films, with a range of c-axis lattice parameters and Tc-values, has been determined as a function of temperature and analysed in terms of the paraconductivity due to direct and indirect fluctuation contributions. We present results on the c-axis coherence length and the phase-relaxation time at 100 K obtained from the fit to the paraconductivity data. The paraconductivity results for optimally doped films were: c-axis coherence length: ξc(0) = 1.25 Å; pair-breaking parameter: δ = 0.05; phase-relaxation time at 100 K: τϕ = 0.066 ps; and two-three-dimensional crossover temperature: T+ = 96.6 K. These values are in good agreement with those from other published work. There was considerable scatter in the coherence length and phase-relaxation time for films with different critical temperatures and oxygen contents. These results were process dependent but appear to be related to the 60 K phase transition in the Tc-x phase diagram.

The design of an ac magnetic induction susceptometer is described and results given for bulk YBCO samples in parallel and perpendicular applied fields and thin film YBCO samples in perpendicular applied fields. The susceptometer employs a double-differential technique designed to accept bulk or thin film samples mounted parallel or perpendicular to the applied field. Theoretical details are given regarding the particular methods used to calculate the complex external and internal susceptibility, flux density and magnetization and the validity of the quadrature detection technique. Performance details of the susceptometer are provided regarding the system sensitivity for frequencies 20, 50 and 100 Hz. Complex susceptibility results are given as a function of applied field magnitude and frequency for the various specimens analysed. The results obtained are compared with Bean plate theory and the critical currents for intergranular and intragranular regions are determined.

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A study has been made of the growth behaviour of zinc selenide deposited from the vapour phase on to (100) germanium surfaces. The deposition has been performed upon clean, restructured Ge (100) 2*2 and ordered, oxygen covered Ge (100) 1*1 surface structures in conditions of ultra-high vacuum (10-9-10-10 Torr). Prior to deposition the germanium surfaces were assessed with low-energy-electron diffraction and Auger electron spectroscopy. An investigation has then been made of the influences that substrate temperature, substrate contamination (specifically oxygen) and degree of vapour saturation have in controlling the growth behaviour of zinc selenide deposited on to these structurally ordered germanium surfaces.

The limitations of conventional a.c. capacitance measuring techniques, for such measurements as MIS interface capacitance and measurements of large value electrolytics, has lead to a demand for new methods of capacitance measuring. This article reviews two new approaches which are presently being employed the quadrature P.S.D. technique and time encoded ballistic techniques.

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