The structural and electronic properties of monovalent sidewall functionalized double-walled carbon nanotubes

► (6,0)@(13,0) DWCNT, built from (6,0) and (13,0) SWCNTs, is a metallic nanotubes. ► NH2/(6,0)@(13,0) and COOH/(6,0)@(13,0) is semimetal and semiconductor, respectively. ► In NH2/(6,0)@(13,0) electrons transferred mainly from inner tube to NH2 group.