Vertical III-V nanowire device integration on Si(100).

We report complementary metal-oxide-semiconductor (CMOS)-compatible integration of compound semiconductors on Si substrates. InAs and GaAs nanowires are selectively grown in vertical SiO2 nanotube templates fabricated on Si substrates of varying crystallographic orientations, including nanocrystalline Si. The nanowires investigated are epitaxially grown, single-crystalline, free from threading dislocations, and with an orientation and dimension directly given by the shape of the template.

Selective area growth of III-V nanowires and their heterostructures on silicon in a nanotube template: towards monolithic integration of nano-devices.

We demonstrate a catalyst-free growth technique to directly integrate III-V semiconducting nanowires on silicon using selective area epitaxy within a nanotube template. The nanotube template is selectively filled by homo- as well as heteroepitaxial growth of nanowires with the morphology entirely defined by the template geometry. To demonstrate the method single-crystalline InAs wires on Si as well as InAs-InSb axial heterostructure nanowires are grown within the template.

Carrier profiling of individual Si nanowires by scanning spreading resistance microscopy.

Individual silicon nanowires (NWs) doped either by ion implantation or by in situ dopant incorporation during NW growth were investigated by scanning spreading resistance microscopy (SSRM). The carrier profiles across the axial cross sections of the NWs are derived from the measured spreading resistance values and calibrated by the known carrier concentrations of the connected Si substrate or epi-layer. In the case of the phosphorus ion-implanted and subsequently annealed NWs, the SSRM profiles revealed a radial core-shell distribution of the activated dopants.

Ex situ n and p doping of vertical epitaxial short silicon nanowires by ion implantation.

Vertical epitaxial short (200-300 nm long) silicon nanowires (Si NWs) grown by molecular beam epitaxy on Si(111) substrates were separately doped p- and n-type ex situ by implanting with B, P and As ions respectively at room temperature. Multi-energy implantations were used for each case, with fluences of the order of 10(13)-10(14) cm(-2), and the NWs were subsequently annealed by rapid thermal annealing (RTA). Transmission electron microscopy showed no residual defect in the volume of the NWs.