Codoping of Potassium and Bromine in Carbon Nanotubes: A Density Functional Theory Study

We investigate the co-doping of potassium and bromine in single-walled carbon nanotubes (SWCNTs) and double-walled carbon nanotubes (DWCNTs) based on density functional theory. In the co-doped (6,0) SWCNTs, the
4s electron of potassium is transferred to nanotube and Br, leading to the n-type feature of SWCNTs. When potassium is intercalated into inner tube and bromine is put on outer tube, the positive and negative charges reside on the outer and inner tubes of the (7,0)@(16,0) DWCNT, respectively. It is expected that DWCNTs would be an ideal candidate for p--n junction and diode applications.