B3LYP/cc-pVTZ study on the growing pattern of small Al/P clusters

V. FERRARESI CUROTTO; R. PIS DIEZ

Centro Atómico Constituyentes, San Martín, Buenos Aires

Workshop; At the frontiers of Condensed Matter V; 2010

CNEA

Semiconductors formed by group 13/15 elements have growing importance due to the potential application in the preparation of thin films for electronic devices [1]. The interest in the study of AlN atomic clusters is based on the fact that the application in thin films requires a profound understanding of properties at atomic level as well as the growing pattern followed by the aggregates. Results obtained for clusters up to five atoms are reported, with emphasis on the growing pattern followed for the aggregates. Al/P aggregates were studied with tools from density functional theory (DFT); using the B3LYP hybrid exchange and correlation functional [2],with cc-pVTZ triple-³ basis functions [3], as implemented in the Gaussian 03 program [4]. Equilibrium geometries were obtained starting from the AlP dimer and adding up aluminium and phosphorus atoms to grow the aggregates. The increase in the binding energy per atom was used to evaluate the growing. The preferred growing pattern was found to be AlP (3A)- AlPP (2A) - PAlPP (3A) - PPAlPP (2A). Molecular electrostatic potentials (MEP), spin densities and charges derived from electrostatic potentials were calculated to get a quantitative picture of the whole process. It is found that Al-P clusters tend to grow following a non planar pattern, preferring zones in which MEP’s are negative and were unpaired electrons are located.[1] S. Nakamura, In Proceedings of International Symposium on Blue Laser and Light Emitting Diodes; A. Yoshikawa, K. Kishino, M. Kobayashi, T. Yasuda, Eds.; Chiba University Press: Chiba, 1996; p 119.[2] A. D. Becke and J. Chem. Phys. 98 (1993) 5648; C. Lee, W. Yang and R. G. Parr, Phys. Rev. B 37 (1988) 785.[3] T. H. Dunning, Jr. J. Chem. Phys. 90 (1989) 1007; T. H. Dunning, Jr. J. Mol. Struct. 388 (1996) 339.[4] M. J. Frisch, et al., Gaussian, Inc., Wallingford CT, 2004, Gaussian 03, Revision D.01.