Electrical and Structural Properties of Si_1-Ge Nanowires Prepared from a Single-Source Precursor

Si_1-Ge nanowires (NWs) were prepared by gold-supported chemical vapor deposition (CVD) using a single-source precursor with preformed Si-Ge bonds. Besides the tamed reactivity of the precursor, the approach reduces the process parameters associated with the control of decomposition characteristics and the dosing of individual precursors. The group IV alloy NWs are single crystalline with a constant diameter along their axis. During the wire growth by low pressure CVD, an Au-containing surface layer on the NWs forms by surface diffusion from the substrate, which can be removed by a combination of oxidation and etching. The electrical properties of the Si_1-Ge/Au core-shell NWs are compared to the Si_1-Ge NWs after Au removal. Core-shell NWs show signatures of metal-like behavior, while the purely semiconducting NWs reveal typical signatures of intrinsic Si_1-Ge. The synthesized materials should be of high interest for applications in nano- and quantum-electronics.