Structural and electronic properties of III-P compound nanotubes by first principle study

Based on density functional theory, the structural and electronic properties of three typical III-phosphide (BP, AlP and GaP) nanotubes were studied by first principle calculation. The computed lattice constants and band gaps of three bulk structures using generalized gradient approximation (GGA) agree well with experimental data. For the nanotubes, the calculation demonstrated that the BP, AlP and GaP nanotubes were energetically stable. All the BP nanotubes are direct band gap semiconductors regardless of their chiral. In contrast, only zigzag AlP and GaP nanotubes are direct band gap semiconductors while armchair type nanotubes are indirect band gap. Furthermore, the band gaps of the nanotubes become wider as the tube diameter increases, indicating that the band gaps can be varied with nanotubes´ structures.