Experimental and theoretical investigations of the morphological and chemical roughness of interfaces in multilayer structures, and the evolution of such roughness with growth and processing conditions, will be conducted. The evolution of roughness and the effect of interruption by the introduction of a new layer will be investigated, as will be the influence of strain on growth front roughness. X-ray diffraction measurements of buried interfaces will be compared to STM measurements of growth front correlation functions. Statistical mechanical methods will be used to develop models for growth of multilayer structures in which kinetic processes change periodically. Luminescence and electrical measurements will be correlated where possible. Studies will initially focus on Si/SiGe and III-V compound superlattices. %%% Interfaces between chemically or structurally distinguishable layers are critically important in the performance of a host of devices, including photonic, electronic, or optical, whose unique properties depend on the multiple layering of thin films. In such structures, interfaces play a decisive role in performance. This research will enhance our understanding of the influence of interface quality on device performance by providing quantitative measures of interface morphology and correlation to electrical and optical properties. In particular, the connection with growth and processing condition will be explored, with the prospect of improved technology for the fabrication of multilayer-film devices.
