Spatial Carrier Confinement in Core-Shell and Multishell Nanowire Heterostructures

We have derived an analytical effective-mass model and employed first-principles density functional theory to study the spatial confinement of carriers in core-shell and multishell structured semiconductor nanowires. The band offset effect is analyzed based on the subband charge density distributions, which is strongly dependent upon the strain relaxation. First-principles calculation results for spatially confined Si/Ge and GaN/GaP nanowires indicate accumulation of a Ge-core hole gas and a GaN-core electron gas, respectively, in agreement with experimental observations.