Structure and Stability of GaS Fullerenes and Nanotubes

Recently, polyhedral; octahedral fullerene‐like structures and cylindrical nanotubes of gallium sulfide have been produced in far from equilibrium conditions using a high power solar synthesis and Pb as growth promoter. Their exact atomistic structure and their formation path remain unknown. Here, the models of fullerenes and nanotubes are designed for both stable β‐ and metastable γ‐polymorphs of GaS. Their stability and electronic properties were investigated as a function of both the morphology and size using density‐functional tight‐binding method. The results manifest that, construction principles for GaS fullerenes are different from those for “classical” dichalcogenide fullerenes. In contrast to the bulk, the kinetic stability of fullerene‐like structures of the γ‐GaS phase is found to be larger, than that for β‐GaS which is ascribed to a sterical specificity of intersected γ‐GaS layers. We predict that, the γ‐GaS phase should arise at least as an intermediate state during the synthesis of polyhedral GaS nanoparticles. Notwithstanding the polymorphic type, the size and the morphology of GaS nanostructures, they are all semiconductors. Finally, the possible composition and electronic properties of Pb||GaS interface within the Pb@GaS nanoparticles are discussed.