Dynamics of Local Vibrational Modes in Semiconductors

College Of William And Mary, Williamsburg VA

Investigators

Abstract

The goal of this project is to elucidate the dynamics of local vibrational modes (LVMs) in semi-conductors, and to connect the rates and pathways of vibrational energy flow to thermally and electronically stimulated defect and impurity reactions and migration in semiconductors. The ap-proach is to perform high-resolution infrared absorption spectroscopy, transient bleaching and photon-echo experiments to measure the vibrational lifetime and dephasing time of point defects related to H, B, C, O, and N as a function of dopant concentration, temperature, uniaxial stress and isotope substitution. These studies will assist evaluation of energy relaxation mechanisms and further understanding of the interaction of hydrogen with dopant impurities in semiconduc-tors. Materials of interest include doped Si, Ge, and GaX (X = As, N, P). Additionally, questions will be addressed regarding vibrational relaxation and transfer channels, coupling to bending modes, and the role of local structure and crystal site in the vibrational relaxation process. %%% The project addresses fundamental research issues associated with electronic materials having technological relevance. An important feature of the project is the strong emphasis on education, and the integration of research and education. A major focus of the project will be the education of graduate and undergraduate students in an interdisciplinary field including modern optics, ma-terials science and computational modeling. ***