Si Nanowire (NW) field effect transistors (FETs) were fabricated on hard Si and flexible polyimide (PI) substrates, and their electrical characteristics were compared. Si NWs used as channels were synthesized by electroless etching method at low temperature, and these NWs were refined using a centrifugation method to get the NWs to have an optimal diameter and length for FETs. The gate insulator was poly(4-vinylphenol) (PVP), prepared using a spin-coating method on the PI substrate. Gold was used as electrodes whose gap was 8 μm. These gold electrodes were deposited using a thermal evaporator. Current-voltage (I-V) characteristics of the device were measured using a semiconductor analyzer, HP-4145B. The electrical properties of the device were characterized through hole mobility, Ion/Ioff ratio and threshold voltage. The results showed that the electrical properties of the TFTs on PVP were similar to those of TFTs on SiO2. The bending durability of SiNWs TFTs on PI substrate was also studied with increasing bending times. The results showed that the electrical properties were maintained until the sample was folded about 500 times. But, after more than 1000 bending tests, drain current showed a rapid decrease due to the defects caused by the roughness of the surface of the Si NWs and mismatches of the Si NWs with electrodes.

Si nanowire/multiwalled carbon nanotube nanocomposite arrays were synthesized. Vertically aligned Si nanowire arrays were fabricated by Ag nanodendrite-assisted wet chemical etching of n-type wafers using HF/AgNO3 solution. The composite structure was synthesized by formation of a sheath of carbon multilayers on a Si nanowire template surface through a thermal CVD process under various conditions. The results of Raman spectroscopy, scanning electron microscopy, and high resolution transmission electron microcopy demonstrate that the obtained nanocomposite has a Si nanowire core/carbon nanotube shell structure. The remarkable feature of the proposed method is that the vertically aligned Si nanowire was encapsulated with a multiwalled carbon nanotube without metal catalysts, which is important for nanodevice fabrication. It can be expected that the introduction of Si nanowires into multiwalled carbon nanotubes may significantly alter their electronic and mechanical properties, and may even result in some unexpected material properties. The proposed method possesses great potential for fabricating other semiconductor/CNT nanocomposites.

Density functional theory was utilized to investigate the growth of an indium nanowire on a Si (001) buckled surface. A site between the edge of two Si dimers is most favorable when the first In atom is adsorbed on the surface at an adsorption energy level of 2.26 eV. The energy barriers for migration from other sites to the most favorable site are low. When the second In atom is adsorbed next to the first In atom to form an In dimer perpendicular to the Si dimer row, the adsorption energy is the highest among all adsorption sites. The third In atom prefers either of the sites next to the In dimer along the In dimer direction. The fourth In atom exhibited the same tendency showed by the second atom. The second and fourth In adsorption energy levels are higher than the first and third levels as the In atoms consume the third valence electron by forming In dimers. Therefore, the In nanowire grows perpendicular to the Si dimer row on the Si (001) surface, as it satisfies the bonding of the three valence electrons of the In atoms.