Integrated silicon nanowire diodes and the effects of gold doping from the growth catalyst

Abstract

We report on integrated, silicon single-nanowire diodes. Gold catalyst templates, defined by lithography, controlled the location of nanowires grown with a vapor-liquid-solid mechanism. The nanowire growth, by atmospheric-pressure chemical vapor deposition, used SiCl4 diluted in H2 on (100) n-type silicon substrates. Postgrowth oxidation and wet etching reduced the nanowire diameters and removed unintentional small diameter nanowires. Spin-on glass isolated the nanowire tips from the substrate, which were then contacted with aluminum. Current-voltage measurements show rectification and ideality factors consistent with pn junction diodes. However, the gold catalyzed nanowires have much higher than expected hole concentrations that cannot be explained by behaviors reported for gold diffused into silicon.