Formation and structural observation of cesium encapsulated single-walled carbon nanotubesElectronic supplementary information (ESI) available: bright-field STEM images and their corresponding Z-contrast images composed of Cs inside filled and outside doped SWNTs are given. See http://www.rsc.org/suppdata/cc/b2/b210079g/

Cesium encapsulation inside single-walled carbon nanotubes (SWNTs) is for the first time realized by ion irradiation of SWNTs immersed in a magnetized alkali-metal plasma, the configuration of which is confirmed to comprise three varieties by field emission type transmission electron microscopy (FE-TEM) and scanning TEM (STEM) observation.