Adsorption of Na, Mg, and Al atoms on BN nanotubes

Adsorption of three metals (Na, Mg, and Al) on the surface of BN nanotubes (BNNT) has been investigated by using density functional theory. Adsorption energies for Na and Al atoms have been calculated to be about − 0.22 to − 0.61 eV, respectively. Upon the metal adsorption, energy gap between highest occupied and lowest unoccupied orbitals of the tube is dramatically decreased, resulting in enhanced electrical conductivity. However, in the case of Mg atom, the low adsorption energy cannot change electronic property of the tube. The semi-conductive BNNT transform to n-type semiconductor after adsorption of Na atom. The metal adsorption modifies work function of the BNNT and consequently the field-emission current densities of metal-BNNT may be significantly enhanced.

► Adsorption of Na, Mg, and Al atoms on the BN nanotubes (BNNT) was studied.
► Adsorption energies for Na and Al atoms are about − 0.22 to − 0.61 eV, respectively.
► Energy gap of the tube dramatically decreases upon the metals adsorption.
► Semiconductor BNNT transform to n-type ones upon adsorption of Na and Al atoms.
► The field-emission current densities of metal-BNNT may be significantly enhanced.