Photovoltaic Properties of Aluminum Phosphide Nanoarticles

We continue our interest in the clusters of semiconductor materials in this investigation of the physical and chemical properties of Al_mP_n cluster (1 ≤ m ≤ 10, 1 ≤ n ≤ 10). Aluminum phosphide material, usually alloyed with other binary materials, has applications in devices such as light-emitting diodes, besides its use as a pesticide. The goal of this research is to reveal the trends seen in the properties of these clusters that may have implications for technological applications. We used the hybrid ab-initio methods of quantum chemistry, particularly the DFT-B3LYP model, and the Many Body Perturbation Theory (MBPT)/MP2 model, to derive the optimal geometries for the clusters of interest. We compare the calculated binding energies, bond-lengths, ionization potentials, electron affinities and HOMO-LUMO gaps for the various clusters. The optimized geometries that we obtained are various combinations of triangles, squares, rectangles, pentagons and hexagons. For the very small clusters, C_2v and D_2v symmetries dominate. The values of HUMO-LUMO gap decrease as the cluster size increases. We also investigate the effects of crystal symmetries corresponding to the bulk structures.