Controlled in situ boron doping of short silicon nanowires grown by molecular beam epitaxy

Epitaxial silicon nanowires (NWs) of short heights (∼280nm) on Si ⟨111⟩ substrate were grown and doped in situ with boron on a concentration range of 1015–1019cm−3 by coevaporation of atomic Si and B by molecular beam epitaxy. Transmission electron microscopy revealed a single-crystalline structure of the NWs. Electrical measurements of the individual NWs confirmed the doping. However, the low doped (1015cm−3) and medium doped (3×1016 and 1×1017cm−3) NWs were heavily depleted by the surface states while the high doped (1018 and 1019cm−3) ones showed volume conductivities expected for the corresponding intended doping levels.