Surface Structure and Chemistry in the Epitaxial Growth of Cadmium Telluride on Silicon
Final rept. 1 Sep 2002-30 Jun 2007
ILLINOIS UNIV AT CHICAGO CIRCLE DEPT OF CHEMISTRY
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The goal of this project was to obtain an atomic-scale understanding of the surface processes that underlie the growth by molecular beam epitaxy MBE of HgCdTe on As-passivated Si surfaces. It is generally recognized that in MBE the first few monolayers determine the quality and structure of the final crystalline film. In principle, the methods of surface science can provide the critically needed information about the initial stages of film growth. However, because of the volatile and toxic nature of As and CdTe, special equipment had to be constructed before the deposition processes could be studied. The resulting unique apparatus allowed us to deposit As and CdTe onto Si substrates in a separate preparation chamber with subsequent transfer under vacuum into the main analysis chamber. We used the apparatus to characterize As on several different Si surfaces with the techniques of scanning tunneling microscopy STM, X-ray photoelectron spectroscopy XPS, and Low Energy Electron Diffraction LEED. The surface analyses were performed with instrumentation that was nearly twenty years old, which slowed progress due to the need for frequent and difficult repairs. Unanticipated budget cuts also impeded progress. Nevertheless, several conference presentations and publications resulted from this work.
- Physical Chemistry
- Atomic and Molecular Physics and Spectroscopy