Self-mask fabrication of uniformly orientated SiGe island/SiGe/Si hetero-nanowire arrays with controllable sizes

We report the synthesis of SiGe island/SiGe/Si hetero-nanowire arrays using laser-induced SiGe islands as templates followed by Ar ion beam etching (IBE). Firstly, single crystal SiGe islands with an average aspect ratio of 0.96 are prepared by pulse laser irradiation of amorphous Ge film on Si substrate. It is interesting to note that these SiGe islands can serve as masks, and uniformly orientated SiGe island/SiGe/Si nanowires can be fabricated by Ar IBE. Moreover, the diameters of the hetero-nanowires can be well-controlled by the size of the SiGe islands determined by the energy density of the pulse laser during the crystallization. Our experiments show the unique nonlithographic self-mask method and demonstrate the mass production of SiGe island/SiGe/Si hetero-nanowire arrays which may find applications in nanodevices.