Synthesis and transistor performances of high quality single crystalline vapor-liquid-solid grown Si_1-xGe_x nanowire

We present a successful synthesis of single crystalline homogeneous Si_1-xGe_x nanowires (diameter: 7~52 nm) via vapor-liquid-solid mechanism. Results show that quality, density, and growth rate of Si_1-xGe_x nanowires are greatly affected by the growth temperature and the single crystalline Si_1-xGe_x nanowires without amorphous sheath layer can be obtained at optimized growth temperature. Control of the amount of Ge in nanowire was obtained with different GeH₄ gas flow rates. Using back-gated field effect transistor integrated with HfO₂ gate dielectric, TaN/Ta metal gate and Pd source/drain electrode, Si_1-xGe_x nanowire transistor exhibits p-MOS operation with I_on/I_off~10⁴, sub-threshold swing of 97 mV/dec.