title: Wafer-scale high-throughput ordered arrays of Si and coaxial Si/Si(1-x)Ge(x) wires: fabrication, characterization, and photovoltaic application.
abstract: We have developed a method combining lithography and catalytic etching to fabricate large-area (uniform coverage over an entire 5-in. wafer) arrays of vertically aligned single-crystal Si nanowires with high throughput. Coaxial n-Si/p-SiGe wire arrays are also fabricated by further coating single-crystal epitaxial SiGe layers on the Si wires using ultrahigh vacuum chemical vapor deposition (UHVCVD). This method allows precise control over the diameter, length, density, spacing, orientation, shape, pattern and location of the Si and Si/SiGe nanowire arrays, making it possible to fabricate an array of devices based on rationally designed nanowire arrays. A proposed fabrication mechanism of the etching process is presented. Inspired by the excellent antireflection properties of the Si/SiGe wire arrays, we built solar cells based on the arrays of these wires containing radial junctions, an example of which exhibits an open circuit voltage (V(oc)) of 650 mV, a short-circuit current density (J(sc)) of 8.38 mA/cm(2), a fill factor of 0.60, and an energy conversion efficiency (η) of 3.26%. Such a p-n radial structure will have a great potential application for cost-efficient photovoltaic (PV) solar energy conversion.
authors: Beijing National Center for Electron Microscopy, Laboratory of Advanced Materials, Department of Material Science and Engineering, Tsinghua University, Beijing 100084, PR China.
authors: Caofeng
authors: C
authors: Pan
authors: Zhixiang
authors: Z
authors: Luo
authors: Chen
authors: C
authors: Xu
authors: Jun
authors: J
authors: Luo
authors: Renrong
authors: R
authors: Liang
authors: Guang
authors: G
authors: Zhu
authors: Wenzhuo
authors: W
authors: Wu
authors: Wenxi
authors: W
authors: Guo
authors: Xingxu
authors: X
authors: Yan
authors: Jun
authors: J
authors: Xu
authors: Zhong Lin
authors: ZL
authors: Wang
authors: Jing
authors: J
authors: Zhu