y was observed in the interface width, that of the Si layer becoming very large. When this was observed, the measured Ge layer thickness was substantially less than the nominal thickness determined from the growth parameters. X-ray diffuse scattering easurements show that the topological roughness was small. The data are interpreted in terms of diffusion of Ge into the Si beneath the Ge layer, a modified Stranski–Krastanov growth mode resulting in the formation of a 3-dimensional "inverted hut" structure of Si-Ge islands. Grazing incidence X-ray scattering provides a rapid and non-destructive technique for the identification of the growth mode. 2003 Elsevier B. V. All rights reserved.

Modulation-doped Al0.22Ga0.78N/GaN heterostructure with 1000 A Si-doped n-Al0.22Ga0.78N barrier (n-AlGaN) were deposited on (0001)-oriented sapphire (-Al2O3) by means of atmosphere-pressure metal-organic chemical vapor deposition. The reciprocal space mappings of symmetric reflection (0002) and asymmetric reflection (1014) were measured with high resolution X-ray diffraction. The results indicate that the microstructure and strain status of barrier correlate to that of the underlying i-GaN layer. The barrier holds an "abnormal" strainrelaxation status, which probably results from the internal defects of n-AlGaN and the strain relaxation status at the i-GaN/-Al2O3 interfaces. The results from grazing incidence X-ray diffraction show that the strain in barrier is nonuniform, which is consistent with the results from the reciprocal space mappings.

The magnetic and electrical properties of crystalline Mn0.05Si0.95 films prepared by post-thermal treatment of the as-deposited amorphous Si-Mn s95 at.%−5 at.%d have been investigated. Both the temperature dependence and field dependence of magnetization were measured using superconducting quantum interference devices, and it has been indicated that the film materials are ferromagnetic with Curie temperature over 400K. X-ray diffraction analysis revealed full crystallization of the films and the incorporation of Mn into the host crystalline Si lattice. Behavior of thermally activated conduction processes of the films has been evinced by electrical property measurement for the films.

HgBa2Ca2Cu3O81 d (Hg-1223) superconducting thin films of about 0.3mm in thickness have been successfully synthesized. The process involves depositing films (1mm thickness) of Ba2Ca2Cu3Ox on a SrTiO3 substrate by pulse laser ablation technique and implanting mercury ions into this deposited film, followed by annealing at oxygen atmosphere. The films so obtained show a relatively wide superconducting transition temperature up to 118K, as determined magnetically, which is similar to that of underdoping bulk Hg-1223.

We have prepared the Y Ca Ba Cu O with xF compounds by the solid state reaction technique. The uperconduct-1yx x 2 3 y ing critical temperature was measured. The structural parameters as a function of Ca substitution were obtained through the detailed analysis of the X-ray diffraction for these Ca-doped samples. The variation of the lattice parameters, some meaningful bond lengths, and the microstrain in lattice change with the Ca content have been discussed.