Direct Measurements of In-Ga Interdiffusion

Rachel S. Goldman

Professor

rsgold@umich.edu

2094 H.H. Dow Building

T: (734) 647-6821

Bio

Projects

Publications

Research Facilities

Group


Direct measurements of diffusion and segregation lengths are generally limited by the inherent averaging that occurs in conventional characterization techniques. We are investigating the atomic-scale dynamics of these processes using a combination of annealing and cross-sectional scanning tunneling microscopy (XSTM). To date, we have studied these issues in a number of heterostructure systems, and have made several important contributions. For example, we used the "wetting layers" between InAs/GaAs quantum dots to directly measure In-Ga interdiffusion and In segregation lengths. To our knowledge, these XSTM studies represent the first direct atom-level measurements of both of these quantities. In addition, we report the first direct evidence for anti-site vacancy diffusion, originally predicted by Van Vechten more than 30 years ago. We are in the process of developing a further understanding of anti-site vacancy diffusion through XSTM studies a variety of mixed anion compound semiconductor heterostructures.