John P. Leonard

 

Assistant Professor, Department of Mechanical Engineering and Materials Science

831 Benedum Hall

412-624-3512, 8069(fax)

jleonard@engr.pitt.edu

http://www.engr.pitt.edu/materials/people/facstaff/leonard_john.html

 

 

Delivery of large amounts of concentrated UV energy on nanosecond timescales can effect many changes in materials not easily accessible by other forms of processing.  Assistant Professor Leonard’s research centers on the fundamentals of these processes induced by KrF excimer laser irradiation.  Using projection irradiation, thin metallic films have been melted and laterally recrystallized to form sheet-like crystalline grains with unique arrangements of structural defects in the range 0.5 nm to 2 μm.  A separate project uses the pulsed excimer beam to deposit metals in high-background inert gases to quench the kinetic energy of the plasma plume, resulting in the deposition of nanocrystalline films.

 

 

 

 

 

 

Laterally crystallized grains in 200 nm Cu film on SiO2 substrate, with nanoscale vacancy-aggregate structures appearing as dark spots in lower grai (left).  Nanocrystalline Cr film deposited via pulsed laser deposition on SiO2 (right)