A field-effect transistor (FET) with a channel length of $\text{∼100\hspace{0.05em}}\mathrm{nm}$ was constructed from a small number of individual ${\mathrm{V}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{5}}$ fibers of the cross section $\text{1.5\hspace{0.05em}}\mathrm{nm\times 10 nm}.$ At low temperature, the conductance increases as the gate voltage is changed from negative to positive values, characteristic of a FET with $n$ -type enhancement mode. The carrier mobility, estimated from the low-field regime, is found to increase from ${\text{7.7×10}}^{\text{−5}} {\mathrm{cm}}^{\mathrm{2}}\mathrm{/V s}$ at $\text{T=131\hspace{0.05em}}\mathrm{K}$ to ${\text{9.6×10}}^{\text{−3}} {\mathrm{cm}}^{\mathrm{2}}\mathrm{/V s}$ at $\text{T=192\hspace{0.05em}}\mathrm{K}$ with an activation energy of $E_a\text{=0.18\hspace{0.05em}}\mathrm{eV}.$ The nonohmic current/voltage dependence at high electric fields was analyzed in the frame of small polaron hopping conduction, yielding a nearest-neighbor hopping distance of $\text{∼4\hspace{0.05em}}\mathrm{nm}.$

Preformed carbon nanotube thin films (10-20 microm), or buckypapers (BPs), consist of dense and entangled nanotube networks, which demonstrate high electrical conductivity and provide potential lightweight electromagnetic interference (EMI) solutions for composite structures. Nanocomposite laminates consisting of various proportions of single-walled and multi-walled carbon nanotubes, having different conductivity, and with different stacking structures, were studied. Single-layer BP composites showed shielding effectiveness (SE) of 20-60 dB, depending on the BP conductivity within a 2-18 GHz frequency range. The effects on EMI SE performance of composite laminate structures made with BPs of different conductivity values and epoxy or polyethylene insulating layer stacking sequences were studied. The results were also compared against the predictions from a modified EMI SE model. The predicted trends of SE value and frequency dependence were consistent with the experimental results, revealing that adjusting the number of BP layers and appropriate arrangement of the BP conducting layers and insulators can increase the EMI SE from 45 dB to close to 100 dB owing to the utilization of the double-shielding effect.