The X-ray optics for high-resolution X-ray topography during the in situ molecular beam epitaxial growth of InGaAs on GaAs were considered. An analysis of dislocation contrast, intensity and geometrical distortion revealed that the use of the 224 reflection in the Bragg geometry at a wavelength of 0.148nm was optimum for double-crystal topography experiments. It was shown experimentally that an 004 channel-cut monochromator was best, and resulted in a significant reduction in exposure times. Images of misfit dislocations were presented which included the first evidence for phase contrast from lattice distortions.

X-Ray Optics of in situ Synchrotron Topography of InGaAs on GaAs B.K.Tanner, A.M.Keir, P.Möck, C.R.Whitehouse, G.Lacey, A.D.Johnson, G.W.Smith, G.F.Clark: Journal of Physics D, 1999, 32[10A], A119-22