First principles study of Si-doped BC2N nanotubes

Stability, and optical and electronic properties of ultrathin h-BNC

Spin polarized density functional theory has been used to study the stability, and electronic and optical properties when BN nanodomains are embedded in graphene and carbon patches are embedded in a single layer of h-BN forming h-BNC nanosystems. Our results show that graphene doped with BN nanodomains exhibits a non-zero gap, which depends on the nanodomain's shape and width. For h-BN with C domains we observe that we can tune the h-BN gap into the visible region, making the h-BNC a promising material for catalysis using solar energy. Furthermore, n-type and p-type semiconductors can be obtained by controlling the bond (C-N or C-B) in the border of the domain. These findings open the possibility to use h-BNC nanosheets for future applications in photocatalysis and optoelectronic devices.

The structure, stability, and electronic properties of ultra-thin BC2N nanotubes: a first-principles study

Rapid developments of the silicon electronics industry have close to the physical limits and nanotube materials are the ideal materials to replace silicon for the preparation of next generation electronic devices. Boron-carbon-nitrogen nanotubes (BCNNT) can be formed by joining carbon nanotube (CNT) and boron nitride nanotube (BNNT) segments, and BC2N nanotubes have been widely and deeply studied. Here, we employed first-principles calculations based on density function theory (DFT) to study the structure, stability, and electronic properties of ultra thin (4 Å diameter) BC2N nanotubes. Our results showed that the cross sections of BC2N nanotubes can transform from round to oval when CNT and BNNT segments are parallel to the tube axis. It results when the curvature of BNNT segments become larger than CNT segments. Further, we found the stability of BC2N nanotubes is sensitive to the number of B-N bonds, and the phase segregation of BNNT and CNT segments is energetically favored. We also obtained that all (3,3) BC2N nanotubes are semiconductor, whereas (5,0) BC2N nanotubes are conductor when CNT and BNNT segments are perpendicular to the tube axis; and semiconductor when CNT and BNNT segments are parallel to the tube axis. These electronic properties are abnormal when compared to the relative big ones.

A DFT study on electronic structure and local reactivity descriptors of pristine and carbon-substituted AlN nanotubes

A density functional theory study was carried out to investigate the structural and electronic structure properties of pristine and carbon-substituted (6,0) aluminum nitride nanotubes (AlNNTs). We examine the usefulness of local reactivity descriptors to predict the reactivity of AlN atomic sites on the external surface of the tubes. The properties determined include the Fukui function f(k) and local softness s(k) on the surfaces of the investigated tubes. According to the values of f(k) and s(k) for the pristine AlNNT, the aluminum atoms are highly preferred sites for nucleophile addition. More especially, the aluminum atoms in middle portion show different reactivity pattern from those at the edge or cap regions of the nanotube. Our results indicate that the nitrogen atoms adjacent to the substituted carbon atoms are less reactive toward atomic hydrogen chemisorption than those in the pristine one. There is an acceptable correlation between chemisorption energies and reactivity indexes, indicating that f(k) and s(k) provide an effective means for rapidly and economically assessing the relative reactivities of finite-sized AlNNTs.