The fabrication of large-scale sub-10-nm core-shell silicon nanowire arrays
School of Materials Science and Engineering, Key Laboratory of Advanced Materials, Tsinghua University, Beijing 100084, People’s Republic of China
Nanoscale Research Letters 2013, 8:405 doi:10.1186/1556-276X-8-405Published: 1 October 2013
A combination of template-assisted metal catalytic etching and self-limiting oxidation has been successfully implemented to yield core-shell silicon nanowire arrays with inner diameter down to sub-10 nm. The diameter of the polystyrene spheres after reactive ion etching and the thickness of the deposited Ag film are both crucial for the removal of the polystyrene spheres. The mean diameter of the reactive ion-etched spheres, the holes on the Ag film, and the nanowires after metal catalytic etching exhibit an increasing trend during the synthesis process. Two-step dry oxidation and post-chemical etching were employed to reduce the diameter of the silicon nanowires to approximately 50 nm. A self-limiting effect was induced by further oxidation at lower temperatures (750°C ~ 850°C), and core-shell silicon nanowire arrays with controllable diameter were obtained.