title: Anisotropic and passivation-dependent quantum confinement effects in germanium nanowires: a comparison with silicon nanowires.
abstract: Electronic structures of hydrogen-passivated germanium nanowires (GeNWs) along the [100], [110], [111], and [112] directions are studied by using the density functional theory within the generalized gradient approximation. The band gaps of the fully relaxed GeNWs along the [100], [110], and [111] directions are all direct at the smaller sizes, while those of the wires along the [112] direction remain indirect. The magnitude of the band gaps of the GeNWs for a given size approximately follows the order of E(g)[100] > E(g)[111] > E(g)[112] > E(g)[110]. Compared with silicon nanowires, GeNWs exhibit stronger quantum confinement effects. Replacement of H by the more stable ethine group is found to lead to a weakening of the quantum confinement effects of GeNWs.
authors.affiliation: Mesoscopic Physics Laboratory, Department of Physics, Peking University, Beijing 100871, PRC.
authors.forename: Mingwei
authors.initials: M
authors.lastname: Jing
authors.forename: Ming
authors.initials: M
authors.lastname: Ni
authors.forename: Wei
authors.initials: W
authors.lastname: Song
authors.forename: Jing
authors.initials: J
authors.lastname: Lu
authors.forename: Zhengxiang
authors.initials: Z
authors.lastname: Gao
authors.forename: Lin
authors.initials: L
authors.lastname: Lai
authors.forename: Wai Ning
authors.initials: WN
authors.lastname: Mei
authors.forename: Dapeng
authors.initials: D
authors.lastname: Yu
authors.forename: Hengqiang
authors.initials: H
authors.lastname: Ye
authors.forename: Lu
authors.initials: L
authors.lastname: Wang