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We present a quartz tuning-fork-based atomic force microscopy (AFM) setup that is capable of mapping the surface contact resistance while scanning topography. The tuning-fork setup allows us to use etched Pt/Ir tips, which have higher durability and better conductivity than probes used in earlier AFM conductance measurements. The performance of the method is demonstrated with contact resistance measurements of gold lines on silicon dioxide and carbon nanotubes on graphite.

We present a fast, high yield, low cost method for the production of scanning probes with aligned carbon nanotubes protruding from the ends. The procedure is described and images of undercut films are used to demonstrate the improved probe quality for topography measurements. A magnetophoretic model of the attachment and alignment processes is discussed.

We report on the precise placement of a single carbon nanotube (CNT) onto a microlectromechanial system (MEMS) structure. Using a hybrid atomic force microscope/scanning electron microscope (AFM/SEM) system, an individual multiwalled CNT was retrieved from a cartridge by the AFM tip, translated to a MEMS device, and then placed across a gap between an actuating and a stationary structure. Progress toward a resistance versus stress/strain measurement on a CNT will be discussed, including SEM images of a MEMS structure we have designed specifically for such a measurement. © 2002 American Institute of Physics.

Radio frequency (rf) antennae, coated with glass, were inductively coupled to an Ar plasma inside the processing chamber. Coupling efficiency η and electron density Ne were measured for moderate pressures (0.1–200 T) and rf power (10–2000 W). Decreasing the dielectric thickness between the antenna and the Ar led to an increase in η and a decrease in Ne. Instabilities and hysteresis were observed for the internal antennae.

We report an extended Hall‐effect study of ion‐bombarded poly(benzimididazobenzophenanthroline ladder), which resembles a disordered metal. We have investigated the dependence of carrier concentration and mobility on ion energy and sample temperature during bombardment and on measurement temperature. The dramatic increases in mobility and conductivity with bombardment energy and temperature indicate increased cross‐link density. Concomitant slight decreases in carrier concentration may result from fewer defects in the cross‐linked network. The mobility decreases slightly with measurement temperature while the conductivity is dominated by the gradually increasing carrier density.

Two planar coil designs for a high pressure rf plasma source are investigated using spectroscopic techniques and circuit analysis. In an Ar plasma a truncated version of the commonly used ‘‘spiral’’ coil is found to produce improvements in peak electron density of 20% over the full version. A coil with figure‐8 geometry is found to move plasma inhomogeneities off of center and produce electron densities comparable to the spiral coils. Both of these characteristics are advantageous in industrial applications. Coil design characteristics for favorable power coupling are also determined, including the necessity of closed hydrodynamic plasma loops and the drawback of closely situated antiparallel coil currents.

We have fabricated quantum devices from remotely doped Si/SiGe heterostructures. The devices are interferometers (loops) similar in plan to those used in experiments on ballistic GaAs/AlxGa1−xAs devices. The loops are approximately 2r=0.8 μm in diameter with linewidths of w=0.4 μm. We have observed clear Aharonov–Bohm (AB) oscillations that vanish systematically as the carrier temperature increases. Response of up to the second harmonic of the fundamental AB frequency e/h implies a phase coherence length of around Lφ=1.2 μm. In some samples, we see steps in conductance G(Vg) as a function of gate voltage similar to the ballistic mode steps seen in GaAs/AlxGa1−xAs point contacts.

Nanowires comprising a metal (Au) segment and a semiconductor segment (CdSe) were grown through an electrochemical process that allows the shape of the interface between the materials to be abrupt (planar) or to be tailored to form off-axis conical profiles. Polarized light was used to excite plasmons in the exposed end of the Au segment, and emission was studied at the Au:CdSe interface and at the distal end of the nanowire. Both the relative intensities of the emissions and the polarizations of the light from the distal end were correlated with the shapes of the interfaces. It was shown that the emission intensity and the degree of polarization were controlled by the interface shape. Finite difference time-domain studies of different interface shapes support the experimental conclusions.

We have observed clear Aharonov–Bohm oscillations in single and multiply connected rings with up to 20% modulation in conductance. The oscillations persist over a very wide range of conductance (0.1–2.0 e2/h) controlled with a gate. Conductance steps as a function of gate bias are observed for the first time in relatively long single and multiple parallel wires and rings. In 2–4 μm long wires, the conductance steps are in multiples of 2e2/h. In the case of the rings, steps of 0.8 and 1.2 e2/h are observed in one and two loops, respectively.

Heterostructured metal-CdSe-metal nanowires were fabricated by sequential electrochemical deposition of layers of Au and the semiconductor CdSe. Nonlinear I-V curves were observed, and a parameter retrieval model was used to extract the majority carrier mobility of 0.5cm2V−1s−1 for nanowires fabricated with zero deposition current during the exchange of the final CdSe and Au segments. This improved threefold with the application of a small current during the solution exchange. Values for the resistance and the electron density for these nanowires were determined.

The authors have developed steerable locomotive devices as small as 30μm using the inertial impact drive as the thrust method. The devices consist of three-legged, thin-metal-film bimorphs designed to rest on three sharp tips with the device body curved up off the surface. Rapid, thermally induced curvature of one leg leads to stepwise translation on a low friction surface. A focused laser was used to supply energy and its parameters controlled the velocity and direction of motion of the device.

In statistical physics one is trained to think about the properties of large ensembles of particles, and to calculate bulk properties by averaging over many microscopic configurations. Although the quantum mechanical properties of the individual constituents of a macroscopic object are important over some length scale (typically a few lattice spacings), they are usually not correlated across the whole object. We are, however, becoming acquainted with more and more disordered systems for which this effective length scale, at low temperatures, can be 100–10 000 times the characteristic microscopic scale; the correlation can involve more than 1011 particles. Such phenomena occur in an intermediate “mesoscopic” regime that lies between the microscopic world of atomic and molecular orbitals and the thoroughly macroscopic world where averages tell all. The wealth of novel quantum coherence phenomena recently observed in this intermediate size regime is the subject of this article.