Confocal Raman spectromicroscopy for tin-core/carbon-shell nanowire heterostructure

► Heterostructures of CNTs encapsulated tin nanowires have been characterized. ► The Raman spectra manifest the existence of nano-graphite in amorphous carbon walls. ► The Raman image reproduces the pristine heterostructures of the CNTs as seen in SEM. ► The resultant heterostructures are luminescent. ► The luminescence was attributed to nano-graphite embedded in the amorphous carbon.