Quantum dots embedded into silicon nanowires effectively partition electron confinement

Motivated by the experimental discovery of branched silicon nanowires, we performed theoretical electronic structure calculations of icosahedral silicon quantum dots embedded into pentagonal silicon nanowires. Using the semiempirical method, we studied the quantum confinement effect in the fully optimized embedded structures. It was found that (a) the band gaps of the embedded structures are closely related to the linear sizes of the longest constituting part rather than to the total linear dimension and (b) the discovered atypical quantum confinement with a plateau and a maximum can be attributed to the substantial interactions of near Fermi level electronic states of the quantum dots and nanowire segments.