Interband optical transitions in GaP nanowires encapsulated in GaN nanotubes

This work investigates the optical properties of cylindrical GaP nanowires encapsulated inside GaN nanotubes (GaP@GaN). Many absorption structures are observed in the range of 2.0--4 eV. Calculations are performed to determine the quantized energy levels of electrons and holes confined in the GaP well. Analytical results indicate that the absorption peaks are attributable to interband optical transitions due to the confined carriers in the heterostructure.