Carbon nanotube transistors exhibiting high on-state conductance, carrier mobilities, and on−off ratios are achieved using polymer electrolytes as gate media. Nearly ideal gate efficiencies allow operation at very small voltages without the commonly observed problem of hysteresis in back-gated nanotube and nanowire transistors. By varying the electron donating and accepting ability of the chemical groups of the host polymer, unipolar p or n devices or ambipolar transistors that are stable at room temperature in air are also shown to be easily fabricated. With simple methods such as spin casting of polymer films, high-performance polymer electrolyte-gated nanotube transistors may provide useful components for and an alternative route to developing hybrid electronics.

High performance single-walled carbon nanotube field effect transistors (SWCNT-FETs) fabricated with thin atomic layer deposited (ALD) Al2O3 as gate dielectrics and passivation layer are demonstrated. A 1.5μm gate-length SWCNT-FETs with 15nm thick Al2O3 insulator shows a gate leakage current below 10−11A at −2.5V<Vg<+7V, a subthreshold swing of S∼105mV∕decade, and a maximum on current of −12μA at a reverse gate bias of −1V. Lack of hysteresis in IV characteristics and low low frequency noise indicate high quality oxide-nanotube interface achieved utilizing ALD Al2O3 as gate dielectrics and passivation layer.

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Carbon nanotube electrochemical transistors integrated with microfluidic channels are utilized to examine the effects of aqueous electrolyte solutions on the electron-transport properties of single isolated carbon nanotubes. In particular, pH and concentration of supporting inert electrolytes are examined. A systematic threshold voltage shift with pH is observed while the transconductance and subthreshold swing remain independent of pH and concentration. Decreasing pH leads to a negative shift of the threshold voltage, indicating that protonation does not lead to hole doping. Changing the type of contact metal does not alter the observed pH response. The pH-dependent charging of SiO2 substrate is ruled out as the origin based on measurements with suspended nanotube transistors. Increasing the ionic strength leads to reduced pH response. Contributions from possible surface chargeable chemical groups are considered.

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Low-frequency noise measurements on individual single-walled carbon nanotube transistors exhibiting ambipolar characteristics have been carried out. With a polymer electrolyte as gate medium, low-frequency noise can be monitored in both p- and n-channel operation of the same nanotube under the same chemical environment. 1/ f noise in the p-channel of polymer electrolyte gated nanotube transistor is similar to that of back gate operation. However, most devices exhibit significantly larger noise amplitude in the n-channel operation that has a distinct dependence on the threshold voltage. A nonuniform energy distribution of carrier trapping/scattering sites is considered to explain these observations.

Corundum crystals with basal surfaces have been embedded in a matrix of fine alumina grains and 15 wt% anorthite and heat treated at 1620°C. During the heat treatment, the fine alumina grains and the corundum crystals grow. The corundum basal surfaces that have been scratched grow most rapidly and those with a low dislocation etch pit density grow most slowly. The corundum basal surfaces with a high dislocation etch pit density grow at an intermediate rate. When the matrix alumina grains are very fine in the initial heat‐treatment stage, all three corundum basal planes grow at approximately the same rate, and, as the matrix grains coarsen, the growth rates of the basal surfaces diverge. The plots of the migration rates of the basal surfaces and the inverse average size of the matrix grains are non‐linear and depend on the estimated dislocation content at the basal surfaces. Such a growth behavior of the basal surfaces resembles those of the singular surfaces of a single crystal growing in a fluid. The results show that dislocations in the grains are important in abnormal growth of grains in liquid matrix.

Self-similar Sierpinski carpet fractals were fabricated using a new nanopatterning technique, i.e. solid-state superionic stamping (S4), to study the effect of feature size on plasmon-enhanced Raman scattering. A real-time Raman image showing electromagnetic (EM) field enhancement contrast is demonstrated. The effects were studied and explained in the context of modes of surface plasmon excitation. Additionally, we find that the EM field enhancement supported by the fractals extends further spatially as compared to continuous Ag surfaces.