New nanomaterials based on In12As12 cages: an ab initio bottom-up study

Abstract

We report the results of density functional calculations on nanostructures of InAs, including the small In_nAs_n (n = 1–15) clusters, the stable hollow cage In₁₂As₁₂ and its derivative nanomaterials (In₁₂As₁₂-based dimer, trimer, nanowire, sheet, and new nanoporous crystal phase). Our results show that among the small In_nAs_n (n = 1–15) clusters, the In₁₂As₁₂ cage structure with T_h symmetry and large HOMO–LUMO gap is proved to be the most stable one, indicating that it would be an ideal building block for the synthesis of cluster-assembled materials. Via the coalescence of In₁₂As₁₂ building blocks, we find that the In₁₂As₁₂ cages can bind into various nanomaterials with different dimensionality by the most stable bonding via In₆As₆ hexagonal faces forming intercluster hexagonal prism. All of these constructed nanostructures are found to be more stable than the individual In₁₂As₁₂ cage and rock salt (RS) phase of InAs. The band analysis reveals that the periodic In₁₂As₁₂-assembled nanomaterials have relative band gap magnitudes of 2.00–4.89 (E_g/E_g,ZB) with respect to the zinc blende (ZB) phase of InAs, and the new nanoporous polymorph holds an indirect gap of ∼0.86 eV, which may extend the range of properties and applications of the InAs compound.