LAUSR

Abstract The electronic properties of nanoclusters, such as Si 60 cage, are remarkably changed by substitution of heteroatom such as Al or P. How do such impure Si 60 cages behave when brought together to form a complex? To address this, we have performed DFT and TD-DFT based calculations on Si 60 Si 60 dimer and Si 59 Al Si 59 P complex. We have explored various electronic properties of Si 59 Al Si 59 P complex and compared with those of Si 60 Si 60 dimer. We notice that the bonding along with binding energies of cages in the complex is slightly different than that of dimer. The higher dipole moment and smaller energy gap of the complex compared to dimer suggest its increased polarity and conductivity. The density-of-state curves reveal that the frontier orbitals of the complex are slightly shifted relative to dimer such that their energy gap is decreased. The electronic excitation analyses suggest that the electronic transition in Si 59 Al Si 59 P complex takes place via charge transfer (CT) mode, and the strength of this CT interaction is much larger than that of Si 60 Si 60 dimer. This is confirmed by larger oscillator strength, larger distance between the centroid of hole and electron as well as larger Δ r index value. We believe that these findings might be useful in the application of Si-nanoclusters in the field of molecular electronics and nanoelectronics.