Interestingly, CNTs can be also produced by the solid-phase transformation of sp2 bonded carbon precursors. For example,double-walled CNTs could be generated in peapods by fusion of encapsulated fullerenes.21−25 Single-walled CNTs with large diameter and multiwalled CNTs can be produced by the coalescence of single-walled CNTs with small diameter.26−31 Very recently, the controlled fabrication schemes of producing graphene nanoribbons (GNRs) have been reported by unzipping CNTs through solution-based oxidation.32 Furthermore, one rational approach is reported to fabricate sub-10 nm GNRs in the oxygen plasma etch process using chemically synthesized nanowires with controllable sizes down to 1 nm with a nearly atomically smooth line edge as an etch mask.33