Plane wave topography on crystals with step-like impurity distributions

Simulation of contrasts in X‐ray plane wave topographs of quartz crystals with induced growth striations

“…For the description of thuch distributions we must work with finite numbers of modulations, as in reality. ALTER et al (1987) used periodical functions ST,(t), which describe the temperature modulation froni minus to plus infinity. I n that case the shape of the density distribution of one period is reproduced quite well, but without the mentioned increase or decrease within one group of modulations.…”

“…However, to use the full information content of the topographs in an optimum way one must have available efficient methods for the simulation and analysis of topographs. ALTER et al (1987) presented a qualitative and quantitative study of the contrast formation in X-ray plane wave topographs of quartz plates with induced growth striations. The aim of the present paper is t o improve the mathematical treatment of such kind of problems by a new approach.…”

“…This is of great importance, because a direct observation of the local growth process is impossible in the case of quartz. Quartz crystals with induced growth striations niay be investigated by nieans of optical (BERNHARDT, ALTER) and X-ray topographical (ALTER, HARTWIG;ALTER et al 1987) methods. Especially in the case of very low changes of the impurity atom/ion concentration, which are the cause of the mentioned growth striations, X-ray plane wave topography is an appropriate experimental method to detect the week lattice distortions of the striations.…”

Study of YBa2Cu3O7 Superconductor by Low-Temperature Scanning Tunneling Microscopy and Spectroscopy

“…Here I M is the maximum intensity and θ A the Bragg angle for a (perfect) reference region [18]. On the present level of approximation this equation is exact.…”

X-Ray Topographic Contrast of Threading Dislocations in Silicon on Insulator Structures

“…To fulfill this criterion in the transmission case, 68 has to be almost constant within the Borrmann triangle. Under this condition the contrast can be described by a shift of the working point on the rocking curve as a function of the value of 68 [18]. Even if the mentioned condition is not fulfilled, this description may still provide a good qualitative interpretation of the defect contrast.…”