Experimental and theoretical investigation on binary semiconductor clusters of B/Si and Al/Si

Abstract

AbstractASi (A = B and Al; n = 1–6) binary cluster anions were generated by laser ablation of samples composed of mixtures of Si and A (A = B and Al), and studied in the gas phase by tandem time‐of‐flight mass spectrometry. Some abundant ions are present in the mass spectrum, indicating that the clusters with these ions have stable structures. The structures of ASi clusters were investigated theoretically by the density functional theory (DFT) method and the energetically lowest‐lying structures were obtained. The binary clusters BSi and AlSi, with the same number of n, share different geometric structures except for ASi with n = 1 and 6, which have the same geometric structures in the ground state. For all the anionic clusters ASi, the lower spin state is lower in energy than the higher spin state in their optimized structures except for the linear ASi− anions, for which the triplet state is lower in energy than the singlet. Calculations of the bonding energy (BE), energy gain (Δ) and HOMO‐LUMO energy gaps confirm that the cluster ASi has a very stable structure, which agrees well with the experimental results. Copyright © 2007 John Wiley & Sons, Ltd.