Controllable Fabrication of GeSi Nanowires in Diameter of About 10 nm Using the Top-Down Approach**Supported by the State Key Program of the National Natural Science Foundation of China under Grant No 61335002, the National High Technology Research and Development Program of China under Grant No 2015AA016904, the National Natural Science Foundation of China under Grant No 11574102, and the National

Abstract

Ordered GeSi nanowires with a ∼10 nm cross section are fabricated utilizing top-down and Ge condensation techniques. In transmission electron microscopy measurements, the obtained GeSi nanowires exhibit a singlecrystal structure and a smooth Ge/SiO2 interface. Due to the linear relationship between the cross-section area and the initial pattern size under the self-limited oxidation condition, the cross-section size of GeSi nanowires can be precisely controlled. The Raman spectra reveal a high Ge fraction (up to 97%) and a biaxial strain of the GeSi nanowires. This top-down technique is promising for fabrication of high-performance GeSi nanowire based optoelectronic devices.