Surface and Intrinsic Conduction Properties of Au-Catalyzed Si Nanowires

An original atomic force microscopy (AFM) method is used to probe surface conduction properties of Au- catalyzed (111) oriented Si nanowires (NWs) attached on the substrate on which they were grown. Drastically different transport regimes are observed upon tuning the electronic junction between the AFM tip and NW (AFM tip work function and NW surface states) and temperature, which reveal the interplay between Schottky interface junctions, Au- mediated surface conduction along the NW sidewalls, and conduction through NWs. The method is applied to extract the intrinsic resistance of nominally undoped NWs when removed from surface Au catalyst residues, and provides evidence for transport through Si NWs with effective residual doping as low as ≈10 14 −10 15 cm −3 .