Synthesis of Si nanowires with a thermally oxidized shell and effects of the shell on transistor characteristics

Silicon nanowires (SiNWs) with a single-crystalline Si core and a thermally oxidized shell (core-shell SiNWs) were synthesized by gold-catalyzed chemical vapor deposition followed by rapid thermal oxidation. To synthesize high-quality core-shell SiNWs, the relationship between the growth parameters and the crystallinity was studied. Furthermore, the formation process of the oxide shell was analyzed in detail by transmission electron microscopy. Using SiNWs as channels, back gate-type field effect transistors (FETs) were fabricated on p-type silicon wafers. FETs with core-shell SiNWs channels exhibited smaller hysteresis in the drain current (Id) vs. gate voltage (VGS) characteristics and higher on/off drain current ratio (ION/IOFF) than those with bare SiNWs channels.