The introduction of hydrogen chloride during the in situ doping of silicon nanowires (SiNWs) grown using the vapor-liquid-solid (VLS) mechanism was investigated. Compared with non-chlorinated atmospheres, the use of HCl with dopant gases considerably improves the surface morphology of the SiNWs, leading to extremely smooth surfaces and a greatly reduced tapering. Variations in the wire diameter are massively reduced for boron doping, and cannot be measured at 600 °C for phosphorous over several tens of micrometers. This remarkable feature is accompanied by a frozen gold migration from the catalyst, with no noticeable levels of gold clusters observed using scanning electron microscopy. A detailed study of the apparent resistivity of the NWs reveals that the dopant incorporation is effective for both types of doping. A graph linking the apparent resistivity to the dopant to silane dilution ratio is built for both types of doping and discussed in the frame of the previous results.

We grew Si nanowires by chemical vapor deposition, via the vapor liquid solid growth, using silane as gaseous precursor and gold as catalyst. The results show that the nanowire length depends on their diameter. For nanowires with diameter under 100 nm, the length increases when diameter increases, because of an increase in the growth velocity. For the thicker diameter (d>100 nm), length decreases when diameter increases, due to an apparent incubation time which is all the higher as the diameter is high. We propose a semiempirical model combining Gibbs–Thomson effect and incubation time, which shows good agreement with the experimental data.