X-Ray Standing Wave Studies of Adsorption Geometries at Selected Metal III-VSemiconductor Surfaces

摘要

The research under the ONR contract N000l4-92-J-1280 resulted in 19 paperspublished in refereed journals and addressed several issues. The main results of these studies will be briefly summarized below. More details can be found in original publications enclosed at the end of this document. Additionally, one PhD thesis resulted solely and one in part from research of this proposal. The main challenge of this proposal was to apply X-ray standing wave (XSW) technique to study atomic structure of several ordered interfaces. The novel approach adopted in this study was to apply photoelectron detection scheme which allowed us to enhance surface sensitivity of the XSW technique. Additionally, we applied a back reflection configuration to de-emphasize stringent structural requirements put by the technique on the perfection of the substrates. Prior to this proposal XSW technique has been almost exclusively used to study overlayers on Si. The better understood Si and Ge structures has been also studied in our program to test some our approaches. However, most of the research has been performed on more complex III-V and II-VI compound semiconductor surfaces and interfaces. More recently, as a result of the pilot research of this proposal, we were able to study even more complex synthetic material and real minerals. Below we outline some specific areas of research performed under this proposal. jg p.2.