Growth and transport properties of complementary germanium nanowire field-effect transistors

n- and p-type Ge nanowires were synthesized by a multistep process in which axial elongation, via vapor-liquid-solid (VLS) growth, and doping were accomplished in separate chemical vapor deposition steps. Intrinsic, single-crystal, Ge nanowires prepared by Au nanocluster-mediated VLS growth were surface-doped in situ using diborane or phosphine, and then radial growth of an epitaxial Ge shell was used to cap the dopant layer. Field-effect transistors prepared from these Ge nanowires exhibited on currents and transconductances up to 850 muA/mum and 4.9 muA/V, respectively, with device yields of >85%. (C) 2004 American Institute of Physics.