Doping and electrical transport in silicon nanowires

Single-crystal n-type and p-type silicon nanowires (SiNWs) have been prepar ed and characterized by electrical transport measurements. Laser catalytic growth was used to introduce controllably either boron or phosphorus dopant s during the vapor phase growth of SiNWs. Two-terminal, gate-dependent meas urements made on individual boron-doped and phosphorus-doped SiNWs show tha t these materials behave as p-type and n-type materials, respectively. Esti mates of the carrier mobility made from gate-dependent transport measuremen ts are consistent with diffusive transport. In addition, these studies show it is possible to heavily dope SiNWs and approach a metallic regime. Tempe rature-dependent measurements made on heavily doped SiNWs show no evidence for Coulomb blockade at temperatures down to 4.2 K, and thus testify to the structural and electronic uniformity of the SiNWs. Potential applications of the doped SiNWs are discussed.