In the area of extended defects in Si, we study the nucleation, growth, and ripening of dislocation loops formed by shallow ion implantation and post-implantation annealing. The interaction of these loops with metallic atoms such as Ni and Ti is investigated. We also investigate the screw dislocation networks, or small angle twist-type grain boundaries, in Si bicrystals formed by wafer bonding. Again we examine the interaction of diffused or implanted metallic atoms with these dislocation networks. In the area of soft condensed matter, we explore the behavior of rheologically active materials.
Rheological materials consist of insulating fluid and micron size solid particles.
They response to electric or magnetic field with a large change in viscosity or in shear resistance. Since a major difference between solid and fluid is that the latter has no resistance to shear, the response to shear by the rheologically active materials is therefore of basic and technological interests. We study the synthesis of solid particles and the microstructure and kinetics of phase changes of particle aggregates in the fluid under the applied field.