Robust staggered band alignment in one-dimensional van der Waals heterostructures: binary compound nanoribbons in nanotube

Investigations of van der Waals (vdW) heterostructures based on distinct low-dimensional materials have attracted significant attention for higher performance devices. Here we use density functional theory computations to scrutinize the band alignment in one-dimensional (1D) vdW heterostructures. In particular, using nanoribbons (NRs) encapsulated inside nanotubes (NTs) based on ten binary-compounds of group IV-IV and group III-V elements, we identified both momentum-matched and -mismatched type II heterostructures with gaps varying from 0.56 eV to 4.37 eV. In addition, we demonstrate a substantial reduction (up to near 0.95 eV) in the staggered band gap of BN compounds by both transverse electric field and longitudinal tensile strain. These findings are favorable for enhancing light harvesting through a wide spectrum and reducing the carrier recombination; our designed heterostructures are expected to offer opportunities for photocatalytic water splitting with safe storage of H-2 products inside the NTs.