ISSN:0370-1972    

DOI:10.1002/pssb.2221980236

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

ISSN:0370-1972    

DOI:10.1002/pssb.2221980237

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

ISSN:0370-1972    

DOI:10.1002/pssb.2221980238

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

ISSN:0370-1972    

DOI:10.1002/pssb.2221980239

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

ISSN:0370-1972    

DOI:10.1002/pssb.2221980240

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractIt is shown that on the basis of the disordered δ‐phase (space group Fm3m) two ordered equilibrium phases with cubic (δ′‐phase, space group Fd3m) and trigonal (δ″‐phase, space group R3m or P3121) unit cells can be formed in titanium carbide TiC0.62and carbidenitrides TiCxNy(x+y≈︁ 0.63), whereas only a cubic δ′‐phase has been observed in TiC0.62Hy. With increasing temperature the low temperature trigonal δ″‐phase transforms at about 1053 K to the cubic δ′‐phase which experiences disordering. The formation of the cubic δ′‐phase at temperatures lower than 1053 K is explained by the difference between the order o

ISSN:0370-1972    

DOI:10.1002/pssb.2221980202

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractElectron paramagnetic resonance and optical absorption in the visible and infrared regions have been used to study flux‐grown KTiOAsO4crystals doped with In, Sc, and Fe. An unstable broad absorption band and paramagnetic hole centres in KTA: In or Sc after γ‐irradiation are observed. The analysis of EPR data leads to a model wherein the holes are trapped on bridging oxygen ions between two titanium ions. The optical absorption band at 2.7 eV is ascribed to the light‐induced transfer of holes from one oxygen ion to another. Infrared absorption bands at 3584 and 3594 cm−1are observed in all crystals and possible positions of the OH group in the structure are d

ISSN:0370-1972    

DOI:10.1002/pssb.2221980203

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractEnergies for emission of a half‐rectangular dislocation loop from a mode I crack tip are investigated in the present work. Optimum aspect ratio of length to width of the half‐rectangular loop, critical dislocation size, and activation energy for dislocation emission are calculated by determining the saddle point of the total energy profile as a function of the length and the width. The activation energy obtained for the half‐rectangular loop is less than a quarter of that obtained for a semicircu‐ lar loop. The effects of the self‐energy correction parameter and the radius of the dislocation core on the activation energy are also repo

ISSN:0370-1972    

DOI:10.1002/pssb.2221980204

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe geometry of threading dislocations (TDs), non‐equilibrium defects that are generated as a result of stress relaxation in thin films, is considered in order to provide a basis for their reduction behavior during heteroepitaxial growth. This paper, the first of a two‐part series, discusses the geometric possibility for reactions between TDs as a result of film growth. It is demonstrated that effective TD motion and reaction are responsible for their overall reduction. The reactions become possible if pairs of TDs come within a critical distance: γAfor annihilation reactions, γFfor fusion reactions, and γSfor scattering reactions. The model is used to explain the experimentally observed l/h(his the film thickness) dependence on TD density. The crystallographic consideration of TDs in the case of (001) growth of f.c.c. semiconductor films is presented and possible reactions between TDs in this case are an

ISSN:0370-1972    

DOI:10.1002/pssb.2221980205

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe theory of Huang scattering of point defects in hexagonal crystals is treated. The concept of “elementary defects” which is based on group theoretical methods is introduced. From this point of view, point defects in hexagonal crystals can be understood as unique superpositions of three types of incoherent elementary scattering defects. These elementary defects reflect characteristical defect symmetries. This concept yields a simple analytical expression for the Huang intensity in the case of arbitrary scattering vectors. The derived intensity function may be a useful tool for the investiga‐ tion of defect structures in h.c.p. metals by Huang scattering measure

ISSN:0370-1972    

DOI:10.1002/pssb.2221980206

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY