Professor of Material Science and Engineering
Current research focuses on understanding the relationships between atomic structure and materials properties at surfaces and interfaces in a wide variety of material systems. To this end, the evolution of epitaxial and textured growth is engineered to produce nanostructured films with specific functional properties for applications in electronic materials, optical materials and tribological materials. Recent work includes the use of femtosecond lasers to deposit films as well as to control the kinetics on growing surfaces by irradiation of the substrate. Ultrafast laser/material interaction is being studied in detail to understand the fundamental mechanisms which drive ablation and collateral damage. Our work focuses on the damage and material removal processes in metals and semiconductors. We use a variety of characterization techniques including pump-probe ultrafast microscopy, femtosecond Laser Induced Breakdown Spectroscopy (fsLIBS), dual pulse LIBS, optical and scanning electron microscopy, transmission electron microscopy, and a variety of in-situ probes. Recently we discovered a novel approach to nano and micro fluidic channel manufacturing using ultrafast lasers. We are pursuing the development of this technique. One major area of interest is the behavior of advanced electronic materials at metal/semiconductor interfaces. The goals of this program are directed at understanding the ultra high vacuum, molecular beam epitaxy (MBE) growth of thin, epitaxial films on silicon. Knowledge of the way in which growth conditions are related to the atomic structure and morphology of the epitaxial films is central to producing high quality, well-characterized, single crystal films. Once a film can be grown with atomic perfection, it becomes an easier task to relate macroscopic properties (electrical, optical, mechanical, magnetic, etc.) to the details of the structure. A large arsenal of experimental techniques are used for the characterization of these films both during and after growth. In-situ characterization includes Auger electron spectroscopy, low energy electron diffraction, reflection high energy electron diffraction, and photoelectron spectroscopies. Ex-situ characterization methods include transmission electron microscopy (conventional and atomic imaging), scanning tunneling microscopy, low angle x-ray diffraction, ion channeling spectroscopy, etc.
Another area of interest is understanding the atomistic reasons for the amorphous to crystalline transformation in low temperature Si(100) homoepitaxy. The key to this phenomena has been eluding the community for some time. Roughness which develops at the growth surface is the prime candidate for study. Recent results conducted in this program have led to a model which explains this transformation in terms of the growth of facets from the rough film.
Post doc. : AT&T Bell Laboratories, Murray Hill, NJ, 1987-1989