is pleased to announce a
Colloquium
with
Anil K Kandalam
Group III nitride materials have been a subject of several theoretical and experimental studies, due to their applications in opto-electronic industry. A first principles calculation, based on the Generalized Gradient Approximation (GGA) to density functional theory was initiated to study the structural and electronic properties of AlnNn, GanNn, and InnNn (n=1-6) clusters.
The results for small polyatomic nitride clusters (monomer, triatomic and dimer) were presented earlier. These small clusters have a strong tendency to form N-N multiple bonds. However, starting from the trimers M3N3, a distinct structural difference between the lowest energy configurations of AlnNn and that of GanNn and InnNn clusters was observed. For AlnNn clusters, the metal-nitrogen bond is found to dominate the lowest energy configurations. As the cluster size is increased from Al3N3 to Al6N6, a transition from planar ring structures towards a bulk-like three dimensional configuration was seen. However, in GanNn and InnNn clusters, the lowest energy structures are mostly planar and are dominated either by N2 or (N3)- sub-units. The segregation of N atoms within these stoichiometric clusters indicate the possibility of N-defects in the thin-film deposition process.
4:00 p.m., Fisher Room 139
Refreshments will be served