ИСТИНА

A substantial shift of Fermi level down into the valence band has been demonstrated recently for single-wall carbon nanotubes (SWCNTs) filled with CuCl by gas-phase technique (Fedotov et al., PSS B, 2014). The energy level shift may be assigned to variation of work function (WF) at nanotubes surface. Comparative field emission studies were performed in this work for the films of doped and pristine SWCNTs to identify the difference of their WFs. The FE measurements were performed using a flat phosphor screen technique and scanning anode FE microscopy. It was found that emission threshold field does not change with CuCl doping. At the same time other FE parameters such as the slope of Fowler-Nordheim plot demonstrated significant variations. The results of FE measurements and other characteristics of SWCNT films obtained with SEM, TEM, optical absorption and Raman are discussed to reveal a possible mechanism of electronic properties variation for SWCNT after their filling with CuCl.