摘要:

The conditions necessary for driving the reconstruction of a dislocation core by means of helium atoms diffusing along a dislocation pipe are examined. It is shown by a simple model that, unlike in Ge, in which such reconstruction has been achieved, the chances of driving such a reconstruction in Si by helium are rather small. Some hopes may be focused on hydrogen, which is known to diffuse effectively into deformed Si.

ISSN:0950-0839    

DOI:10.1080/09500838808214722

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Some peculiar results of deep-level transient spectroscopy (DLTS) measurements on plastically deformed hydrogenated Si are explained in terms of a model for the driven reconstruction of dislocations. Driven reconstruction may be responsible for the reduction in the density of high-temperature electron paramagnetic resonance (EPR) centres after predeformation and after deformation during heat treatment in a hydrogen atmosphere. The model for driven reconstruction is based on the assumption that the non-reconstructed state is the lowest energy state of the dislocation core. Together with numerous results concerning electrical conduction along dislocation cores, the considerations presented in this Letter strongly indicate that dangling bonds exist within dislocation cores in Si. The absence of a dislocation-related EPR signal suggests that there must be a reason, intrinsic to the dislocation core, by which dangling bonds in dislocations do not carry unpaired electrons.

ISSN:0950-0839    

DOI:10.1080/09500838808214723

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Various [001] twist-(001) boundaries in Cu with dispersed SiO2boundary particles have been observed with a transmission electron microscope. Boundary energies were determined with reference to the isotropic Cu-SiO2interfacial energy by measuring the misorientation-dependent shape of the boundary SiO2particles. When the boundary energy was plotted against misorientation, several energy cusps were clearly recognized at misorientation angles corresponding to low σ values; namely at Σ41A, Σ13A, Σ17A, Σ5 and possibly Σ29A.

ISSN:0950-0839    

DOI:10.1080/09500838808214724

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

We establish in this Letter that the atomic structure of a perfect icosahedral quasicrystal can be achieved in a three-dimensional Penrose tiling of two rhombohedral unit cells, where the cluster atomic decoration defines uniquely two types of faces and their matching rule. The τ3self-similarity ratio defines the hierarchic generation of the tiling, the two types of faces and their matching rule being restored at each step. The structure may be simply understood in terms of four zonohedra: the oblate rhombohedron, a 20-branched stellate zonohedron, the rhombic triacontahedron and the rhombic icosahedron.

ISSN:0950-0839    

DOI:10.1080/09500838808214725

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Heating that occurred during argon-ion bombardment of a thin film of a quasicrystalline phase of an Al─Li─Cu alloy resulted in distortion and subsequent phase transformation. The distortion causes staggering of the diffraction spots in the fivefold symmetry as well as contraction and expansion of the systematic rows parallel to the axis of the symmetry of the distortion which is one of six fivefold axes. The results support the quasicrystalline model of the icosahedral phase which transforms possibly to a cubic phase through an intermediary metastable configuration corresponding to the distorted phase.

ISSN:0950-0839    

DOI:10.1080/09500838808214726

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The stress in dry thermal SiO2has been studied as a function of growth temperature by measuring the curvature of thin oxidized silicon wafers at room temperature. The results show that the curvature of wafers with thin oxide layers is determined by stress in the back-side SiO2. Anin situanneal at the growth temperature leads to relaxation of the initial compressive stress. The stress in the oxide was found to be very sensitive to water content.

ISSN:0950-0839    

DOI:10.1080/09500838808214727

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Relative spectroscopic measurements of the bulk modulus of GaIn As P lattice-matched to InP yield a value within 1% of that of InP. This surprising result is not in agreement with accepted interpolated values but is predicted by Keyes' empirical scaling rule for elastic constants.

ISSN:0950-0839    

DOI:10.1080/09500838808214728

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The large-angle convergent-beam electron diffraction technique has been used to obtain 200 rocking curves from a l500 Å Al,0·4Ga0·6As/30Å GaAs/3500Å Al0·4Ga0·6As sample observed in plan view. It is demonstrated that the rocking curves are sensitive to the presence of the GaAs layer and are in good agreement with simulations calculated from a simple kinematical approach. It is shown that both the layer thickness and depth in the foil may be examined and that GaAs layer thicknesses less than 10 Å in the 5000 Å foil may be detectable.

ISSN:0950-0839    

DOI:10.1080/09500838808214729

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A density of states diagram for the mobility gap of a-Se is constructed by self-consistent analyses of time-resolved xerographic residual and dark depletion potentials in both undoped and halogen- and alkali-doped Se films. These are then combined with analyses of transient transport data to reveal additional features adjacent to the mobility edges. The results are consistent with the suggested existence of oppositely charged diamagnetic defect pairs whose relative population can be significantly and systematically altered by association with halogens and alkalis.

ISSN:0950-0839    

DOI:10.1080/09500838808214730

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Measurements of the optical absorption of thin films of Pb1-xHgxS show a sharp increase in the optical band gap with a small addition of mercury to PbS. It is suggested that the band gap is increased in the films as a result of the formation of new conduction and valence bands.

ISSN:0950-0839    

DOI:10.1080/09500838808214731

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor