Investigation of GaAs/AlAs multilayer systems for optical Bragg reflectors using x‐ray double crystal techniques

1993 ◽  
Vol 73 (5) ◽  
pp. 2220-2224 ◽  
Author(s):  
B. Jenichen ◽  
R. Hey ◽  
M. Höricke ◽  
R. Köhler
Keyword(s):  
Bragg Reflectors ◽  
Double Crystal ◽  
Multilayer Systems ◽  
X Ray

Investigation of Multilayer Systems for Optical Bragg Reflectors by X-ray Double Crystal Topography and - DIF-Fractometry

1991 ◽  
Vol 240 ◽  
Author(s):  
B. Jenichen ◽  
R. Köhler ◽  
R. Hey ◽  
M. Höricke
Keyword(s):  
Stress Relaxation ◽  
Threading Dislocations ◽  
Misfit Dislocations ◽  
Bragg Reflectors ◽  
Double Crystal ◽  
Multilayer Systems ◽  
X Ray ◽  
Different Levels

ABSTRACTOptical Bragg reflectors consisting of the binaries AlAs and GaAs were investigated using double crystal topography and diffractometry. In undoped mirror stacks stress relaxation due to the formation of misfit dislocations was observed, which could be prevented by doping the stacks with 1018cm−3 silicon. In topographs taken in the substrate and different satellite reflections an unusual vanishing of the contrast of different segments of the misfit dislocations takes place, that shows these different segments to be located at different levels of the stack. The contrasts of the threading dislocations are quite similar in the substrate and the satellite reflections whereas the misfit dislocations change their contrast markedly.

A DOUBLE CRYSTAL MONOCHROMATOR FOR SOFT X-RAY BEAM LINE OF UVSOR

1986 ◽  
Vol 47 (C8) ◽  
pp. C8-135-C8-137
Author(s):  
T. MURATA ◽  
T. MATSUKAWA ◽  
M. MORI ◽  
M. OBASHI ◽  
S.-I. NAO-E ◽  
...  
Keyword(s):  
Beam Line ◽  
Double Crystal ◽  
X Ray ◽  
Double Crystal Monochromator

Double Crystal X‐Ray Dilatometer Using Continuous Radiation

1971 ◽  
Vol 42 (2) ◽  
pp. 196-199 ◽  
Author(s):  
Virgil E. Bottom ◽  
Renê Ayres Carvalho
Keyword(s):  
Double Crystal ◽  
X Ray ◽  
Continuous Radiation

Strain Shift Coefficients for Phonons in Si-Ge Heterostructures

1991 ◽  
Vol 239 ◽  
Author(s):  
J.-M. Baribeau ◽  
D. J. Lockwood
Keyword(s):  
Molecular Beam ◽  
Composition Dependence ◽  
Vibration Mode ◽  
Phonon Frequency ◽  
Longitudinal Optical ◽  
Stress Factor ◽  
Double Crystal ◽  
Raman Scattering Spectroscopy ◽  
X Ray ◽  
Shift Coefficient

ABSTRACTStrain shift coefficient measurements for longitudinal optical phonons in molecular beam epitaxy grown metastable pseudomorphic Si1−xGex layers on (100) Si (0 < x < 0.35) and Ge (0.80 < x < 1) are reported. Strain in partially relaxed annealed specimens was obtained by double-crystal x-ray diffractometry and the corresponding strain phonon shift was measured by Raman scattering spectroscopy. For epilayers grown on Si it was found that the epilayer Si-Si phonon frequency varies linearly with strain. The magnitude of the strain shift coefficient b however showed a small composition dependence varying from b ≈ -700 cm-1 at x = 0 to b ≈ -950 cm-1 at x = 0.35, corresponding to a stress factor τ = 0.40 + 0.57x: + 0.13x2 cm-1/kbar. For the Ge-Ge vibration mode in epilayers grown on Ge, b decreased from ∼-425 cm-1 at x = 1 to ∼-500 cm-1 at x = 0.8, corresponding to a stress factor τ ≈ 0.52 – 0.14x - 0.08x2 cm-1/kbar.

Assessment of Thin Heteroepitaxial Layers Using Skew Angle Asymmetrical X-Ray Double Crystal Diffraction

1988 ◽  
Vol 138 ◽  
Author(s):  
S. J. Miles ◽  
G. S. Green ◽  
B. K. Tanner ◽  
M. A. G. Halliwell ◽  
M. H. Lyons
Keyword(s):  
Skew Angle ◽  
Double Crystal ◽  
X Ray ◽  
Heteroepitaxial Layers

Anisotropic Lattice Relaxation and its Mechanism of ZnSe Epilayer Grown on (001) GaAs Substrate by Molecular Beam Epitaxy

1995 ◽  
Vol 399 ◽  
Author(s):  
C.S. Kim ◽  
S.K. Noh ◽  
H.J. Lee ◽  
Y.K. Cho ◽  
Y.I. Kim ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Gaas Substrate ◽  
Molecular Beam ◽  
Rotation Angle ◽  
Lattice Relaxation ◽  
High Dislocation Density ◽  
Sinusoidal Oscillation ◽  
Double Crystal ◽  
X Ray ◽  
Anisotropic Lattice

ABSTRACTWe have investigated anisotropic lattice relaxation and its mechanism of ZnSe epitaxial layer grown on (001) GaAs substrate by MBE. Double-crystal X-ray rocking curves for (004), {115} and {404} reflections were measured as a function of the azimuthal rotation angle of the sample. We observed the sinusoidal oscillation of the FWHM of the epilayer peak for (004) reflections due to the asymmetric dislocation density along two orthogonal <110> directions, and the direction of the maximum FWHM corresponding to high dislocation density is along [110]. In addition, the strain along [110] is smaller than that along [1-10], indicating that the layer suffered anisotropic lattice relaxation. The direction of larger relaxation([l-10]) is not consistent with that of high dislocation density([110]). The results suggest that the asymmetry in dislocation density is not responsible for the anisotropic relaxation of the ZnSe epilayer.

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