Diffraction imaging (topography) with monochromatic synchrotron radiation

Abstract

Structural information of special interest to crystal growers and device physicists is now available from high resolution monochromatic synchrotron diffraction imaging (topography). In this review, the importance of superior resolution in momentum transfer and in space is described, and illustrations are taken from a variety of crystals: gallium arsenide, cadmium telluride, mercuric iodide, bismuth silicon oxide, and lithium niobate. The identification and detailed understanding of local variations in crystal growth processes are shown. Finally, new experimental opportunities now available for exploitation are indicated.

Enhancement of mercuric iodide detector performance through increases in wafer uniformity by purification and crystal growth in microgravity

“…[18][19][20] The resulting images map the incidence and distribution of structural anomalies and provide a basis for the determination of their nature. The images also provide a foundation for understanding and integrating the results of other characterization studies.…”

“…[18][19][20] The images were recorded on nuclear emulsion plates, which provide a spatial resolution of 1 m. They enable comprehensive interpretation of other structural observations obtained through etch- ing, ␥-ray diffraction, calorimetry, and resonance fluorescence spectroscopy. As a result, we are able to establish a structural model and develop an understanding of the sources of irregularity.…”

High resolution diffraction imaging of crystals grown in microgravity and closely related terrestrial crystals

“…Previous collaboration in high-resolution diffraction imaging of terrestrial mercuric iodide with Lodewijk van den Berg [7], who had grown this material himself in space, had verified the prominence in this material of individual grains, as reported following neutron and gamma-ray diffraction [25] and x-ray topography [12] [26]. A 2-6 µm cellular structure had also been reported [13].…”

“…Unexplained cellular structure with a characteristic dimension of 2-6 µm has been observed in all mercuric iodide by scanning cathodoluminescence microscopy [13]. Previous exploratory high-resolution diffraction imaging of terrestrial mercuric iodide on the beam line [7] suggested that high-resolution imaging of additional crystals might prove to be extraordinarily interesting and fruitful in wrestling with these questions.…”

“…Fortunately, recent technical advances 4 .n diffraction imaging with high resolution monochromatic synchrotron x-radiation present a timely opportunity to achieve all of these ends [5][6] [7].…”