The vacancy-type Frank dislocation loops in GaP, which are the origin of shallow etch pit defects, dissolve during heat treatment via outdiffusion of the originating point defects. This forms a defect-free denuded zone under the surface of a GaP wafer. The activation enthalpy of the diffusion process of the gallium vacancy (which corresponds to the formation of the denuded zone) is estimated to be 4.0 eV.

Some properties of ZnSe single crystals grown from melt using a B2O3 encapsulant were investigated. B2O3 encapsulation prevents the crystal from contamination of impurities during growth and improves the crystallinity, specifically by subsequent annealing at 1390°C. However, it is revealed that the concentration of boron in the ZnSe crystal is increased by using B2O3 encapsulant. At the same time, the photoluminescence spectrum of the annealed sample shows characteristic emission peaks at 2.733 and 2.752 eV at 16 K by 16 mW cm−2 excitation of 325 nm emission line from a He-Cd laser. From both the temperature dependence and the excitation intensity dependence of the peak energy, these emissions are identified as a donor-acceptor pair and a conduction-band-to-acceptor emission, respectively. A shallow acceptor level is located at about 70 meV above the valence band. From the facts that the crystal contains 1017–1018 atoms cm−3 of oxygen as an impurity and the formation of this level correlates to the annealing process, isoelectronic oxygen or oxygen associated complex is believed to be a possible origin of the shallow level.

B2O3 is an available encapsulant for the melt growth of ZnSe single crystals with a limited degree of contamination of boron, 1016−6 × 1018 atmos cm−3. It is effective to reduce the density of twins in ZnSe crystals. Through the consideration of the role of B2O3 encapsulant, the generation process of three specified structures of melt-grown ZnSe crystals was interpreted. It is attributed to the different solid-solid transformation mechanisms governed by the nucleation process of the zincblende phase.

The liquids line and the temperature of the solid-solid phase transformation of the system ZnSe near the stoichiometric composition were determined by the modified differential thermal analysis (DTA) technique. The congruent melting point (Tm) of ZnSe was determined to be 1522 ± 2°C, i.e., within the range of the already reported values. The 2H to 3C solid-solid phase transformation temperature is 1411 ± 2°C, 14°C below the reported values. The shape of the observed liquidus line was compared with the theoretical quasiregular and regular associated solution models. It correlates well with the latter solution model, suggesting the existence of associated molecules in the ZnSe melt.

The structure of sputter-deposited Co/Cu multilayer film depends strongly on such preparation conditions as the Ar gas pressure (PAr) and the substrate bias voltage (VB). For films deposited at VB=0 V, the interfaces were flat and the (111) plane orientation was good at low PAr. The (111) orientation was better for ¿30 V films than for 0 V films. The interface was flat at high PAr, in contrast with 0 V films. The giant magnetoresistance (GMR) depended heavily on the layer flatness, the film density, and the existence of crystal grains with an fcc (200) orientation. The effect of annealing on the film structure and GMR was also investigated. Annealing for 10 min. at 200°C in vacuum did not change the film structure very much, but the first GMR peak height of 0 V films decreased significantly, in contrast to the stable second GMR peak.

Co/Cu multilayers have been prepared on glass substrates without buffer layers by rf magnetron sputtering under various conditions. The film structure for establishing the large giant magnetoresistance is suggested to have smooth, flat and sharp interfaces, and close-packed homogeneous Cu layers with low resistivity. The role of the (200) texture is also discussed.

Co/Cu multilayer films were prepared by rf sputtering, both with and with-out a substrate bias voltage VB=-30 V. X-ray diffraction results indicated that the layer boundaries in -30 V biased films are sharper, and the orientation of (111) planes are better, than in films prepared without a bias voltage. In films with zero bias, the MR ratio increases monotonically with the Cu layer thickness dCu u...

Co/Cu multilayers have been prepared on glass substrates by sputtering with negative substrate bias voltage. In zero biased films, the magnetoresistance (MR) increases monotonically with the Cu layer thickness (d/sub Cu/) up to 40 AA, resulting from decoupling between the ferromagnetic layers. On the other hand, for -30-V biased films, three oscillation peaks with a period of about 12 AA appear in the d/sub Cu/ dependence of the MR ratio because of the RKKY-like interlayer coupling. In the oscillation peak at d/sub Cu/=24 AA, a sharp MR change occurs at low applied magnetic field, owing to a very small coupling constant of J=0.008 erg/cm/sup 2/. The Hall resistivity and the planar Hall effect have been also measured. >