The electronic band structure of Nl-doped chiral (4,2) BNT is shown in Figure 11 and found quite different from achiral BNTs.
Thus, nitrogen doping in BNTs enhances both stability  and conductivity in comparison to pristine ones.
It is found that the nitrogen impurity (N) enhances the conductivity of armchair (3,3) BNT. Therefore, the (3,3) BNTs are the most desirable candidate for field emission devices and metallic contacts.
The boron nanotube (BNT) was first proposed by Boustani et al.
The structural stability was predicted high for n-doped BNT in comparison to pristine ones .
First of all we present the electronic band structure of single nitrogen atom (N1) doped BNT as depicted in Figure 3.
It is revealed that two energy levels cross the Fermi level which ensures metallic character as in N1-doped (3,3) BNT. The energy states get dispersive near the Fermi level showing delocalized type nature but remain metallic.
In addition, the band structure of N2-doped (5,0) BNT is demonstrated in Figure 9.
It is also evident from Table 1 that zigzag (5,0) BNT and CNT are metallic while BNNT and SiCNT are semiconducting.