This award is for support of a collaborative research project between Dr. Ching-Yao Fong, Physics Department at the University of California at Davis, and Dr. Selim Ciraci, Physics Department at Bilkent University in Ankara, Turkey. The two scientists propose to investigate both homo- and hetero-epitaxial growths and the role that specific surfactants play in modifying these growth processes on semiconductor surfaces from the most elementary point of view: with one, several and one monolayer adatoms on a surface. The objective is to develop a microscopic understanding that provides a foundation for better control of growth processes. The two scientists will study the basic interaction between the substrate and an incoming atom, or a surfactant, on small size system by using an ab-initio method that is capable of distinguishing between configurations that have small energy differences. The details of the interaction will be used to develop empirical potential energy functions that can accurately describe various low coordination configurations. These functions will be used to study various atomic processes that occur during epitaxial growth. They will analyze the electronic structure of every major step in simulated growth to bridge the gap between the predictions of atomic configurations in real space and the results of scanning tunneling microscopy (STM) experiments. Scope: This project will support collaboration between two teams with complementary capabilities and institutional facilities. Drs. Fong and Ciraci have independently published in this field, and the combination of their expertise would help this research. There are significant capabilities for the experimental work at both UC Davis and at Bilkent University. The project will involve travel of a US graduate student from UC Davis to Bilkent to participate in the research there, and travel by two students from Bilkent to Davis to work in Dr. Fong's laboratory. The knowledge gained in this joint effort will provide theoretical background for technological applications in the design and manufacture of electronic and opto-electronic devices that will benefit both countries. The project fits well within the objectives of the Division of International Programs.
