title: Synthesis of Si/SiO2core-shell nanowire arrays and broadband anti-reflection effects in diluted Si nanowire arrays by adjusting dielectric shell thickness.
abstract: A low filling ratio and enhanced absorption is needed to enable the full potential of Si nanowire (NW) arrays for optoelectronic applications. In this paper, we report a versatile, scalable fabrication technique that uses nanosphere lithography (NSL) patterning for the synthesis of vertically aligned Si and Si/SiO2NW arrays. The optical reflection of the NW arrays can be substantially suppressed by the addition of the transparent shell. Meanwhile, by the finite-difference time-domain (FDTD) simulation, we find that the absorption enhancement in the core Si NW can be obtained by adding the transparent shell. The special absorption enhancement of the Si NW arrays with a core-shell structure can be theoretically understood by modal analysis. The absorption in such Si NW array structures is very sensitive to the thickness of transparent coating. By the addition of a SiO2shell layer, the absorption in the inner Si NW array can be substantially enhanced. Furthermore, significant absorption enhancement and broadband anti-reflection effects can be achieved by the diluted Si NWs combined with the single dielectric shell.
authors.affiliation: Key Laboratory of Material Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China.
authors.forename: Xinhua
authors.initials: X
authors.lastname: Li
authors.forename: Tao
authors.initials: T
authors.lastname: Chen
authors.forename: BuKang
authors.initials: B
authors.lastname: Zhou
authors.forename: Guangqiang
authors.initials: G
authors.lastname: Liu
authors.forename: Tongfei
authors.initials: T
authors.lastname: Shi
authors.forename: Long
authors.initials: L
authors.lastname: Wen
authors.forename: Huaxiang
authors.initials: H
authors.lastname: Cao
authors.forename: Yuqi
authors.initials: Y
authors.lastname: Wang