Silicon nanowires have been identified as important components for future electronic and sensor nanodevices. So far gold has dominated as the catalyst for growing Si nanowires via the vapour-liquid-solid (VLS) mechanism. Unfortunately, gold traps electrons and holes in Si and poses a serious contamination problem for Si complementary metal oxide semiconductor (CMOS) processing. Although there are some reports on the use of non-gold catalysts for Si nanowire growth, either the growth requires high temperatures and/or the catalysts are not compatible with CMOS requirements. From a technological standpoint, a much more attractive catalyst material would be aluminium, as it is a standard metal in Si process lines. Here we report for the first time the epitaxial growth of Al-catalysed Si nanowires and suggest that growth proceeds via a vapour-solid-solid (VSS) rather than a VLS mechanism. It is also found that the tapering of the nanowires can be strongly reduced by lowering the growth temperature.

Large-scale CdS nanowires were achieved by a new, simple, and low cost process based on thermal evaporation of CdS powders under controlled conditions with the presence of Au catalyst. The synthesized CdS nanowires have lengths up to several tens of micrometers and diameters about 60−80 nm. The growth of CdS nanowires is controlled by the conventional vapor−liquid−solid (VLS) mechanism. A strong red emission with a maximum around 750 nm was observed from the synthesized CdS nanowires at room temperature, which was attributed to their surface states. The technique we used is, in principle, generalizable as a means of fabricating other group II−VI semiconductor nanowires.

Molybdenum disulfide (MoS 2 ) with excellent properties has been widely reported in recent years. However, it is a great challenge to achieve p-type conductivity in MoS 2 because of its native stubborn n-type conductivity. Substitutional transition metal doping has been proved to be an effective approach to tune their intrinsic properties and enhance device performance. Herein, we report the growth of Nb-doping large-area monolayer MoS 2 by a one-step salt-assisted chemical vapor deposition method. Electrical measurements indicate that Nb doping suppresses ntype conductivity in MoS 2 and shows an ambipolar transport behavior after annealing under the sulfur atmosphere, which highlights the p-type doping effect via Nb, corresponding to the density functional theory calculations with Fermi-level shifting to valence band maximum. This work provides a promising approach of two-dimensional materials in electronic and optoelectronic applications.