Study on the growth behavior and photoelectron spectroscopy of neodymium-doped silicon nanoclusters NdSin0/- (n = 8-20) with a double-hybrid density functional theory.

Abstract

Structural evolution, magnetic moment, and thermochemical and spectral properties of NdSin0/- (n = 8-20) nanoclusters were studied. Optimized structures for NdSin demonstrated that the configuration with quintet ground state prefers Nd-substituted for a Si of the most stable Sin + 1 (n = 8-11) structure to Nd-linked configuration with Si9 tricapped trigonal prism subcluster (n = 12-19). Finally, the configuration prefers to Nd-encapsulated into Si cage framework (n = 20). For anion, the evolution at the quartet state prefers Nd-linked structure for n = 8-19 (excluded 9), and prefers Nd-encapsulated structure of n = 20. The spectral information including electron affinity, vertical detachment energy, and simulated photoelectron spectroscopy were also observed. The 4f electrons of Nd atom in NdSin with n = 8-10 hardly participate in bonding, but take part in remaining neutral clusters and all anionic NdSin- clusters. The calculations of average bond energy, HOMO-LUMO gap, and chemical bonding analyses reveal that NdSi20- possesses perfect thermodynamic and ideal chemical stability, making it as the most appropriate constitutional units for novel multi-functional semiconductors.