Design of a very thin direct-band-gap semiconductor nanotube of germanium with m

2020-03-12 13:36:08

Nb energy gap nanotube germanium

责任者: Singh, A.K.;Kumar, V.;Kawazoe, Y. 单位: Inst. for Mater. Res., Tohoku Univ., Sendai, Japan 来源出处: Physical Review B (Condensed Matter and Materials Physics)(Phys. Rev., B, Condens, Matter Mater. Phys. (USA)),2005/02/15,71(7):75312-1 摘要: Using ab initio total energy calculations we design a very thin semiconducting nanotube of germanium with a direct band gap by encapsulation of Mo or W. This finding is an outcome of studies of assemblies of Ge18Nb2 clusters into nanotubes. The infinite Nb-doped nanotube is metallic. However, the electronic structure has a significant gap above the Fermi level. When Nb is replaced by a Z+1 element such as Mo or W, it leads to the formation of a semiconducting nanotube. The atomic structure of these nanotubes is based on a novel alternate prism and antiprism stacking of hexagonal rings of germanium. Such an arrangement is optimal for Ge18M2 (M=Nb, Mo, and W) clusters that serve as the building blocks of nanotubes. These results demonstrate that by just changing the M atom in the growth process, we can form metallic, semiconducting, and n or p types of nanotubes, opening new possibilities for nanoscale devices 关键词: ab initio calculations;atomic structure;encapsulation;energy gap;Fermi level;germanium;molybdenum;nanotubes;niobium;total energy;tungsten;direct-band-gap semiconductor nanotube;germanium;metal encapsulation;ab initio total energy calculations;thin semiconducting nanotube;Ge18Nb2 clusters;Nb-doped nanotube;electronic structure;energy gap;Fermi level;atomic structure;alternate prism-antiprism stacking;hexagonal germanium rings;nanoscale devices;p-type semiconductor nanotube;n-type-semiconductor nanotube;Ge:Nb;Ge:Mo;Ge:W