Effect of Source, Surfactant, and Deposition Process on Electronic Properties of Nanotube Arrays

The electronic properties of arrays of carbon nanotubes from several different sources differing in the manufacturing process used with a variety of average properties such as length, diameter, and chirality are studied. We used several common surfactants to disperse each of these nanotubes and then deposited them on Si wafers from their aqueous solutions using dielectrophoresis. Transport measurements were performed to compare and determine the effect of different surfactants, deposition processes, and synthesis processes on nanotubes synthesized using CVD, CoMoCAT, laser ablation, and HiPCO

Effect of Source, Surfactant, and Deposition Process on Electronic Properties of Nanotube Arrays

The electronic properties of arrays of carbon nanotubes from several different sources differing in the manufacturing process used with a variety of average properties such as length, diameter, and chirality are studied. We used several common surfactants to disperse each of these nanotubes and then deposited them on Si wafers from their aqueous solutions using dielectrophoresis. Transport measurements were performed to compare and determine the effect of different surfactants, deposition processes, and synthesis processes on nanotubes synthesized using CVD, CoMoCAT, laser ablation, and HiPCO

RF CIRCUIT MODEL OF A QUANTUM POINT CONTACT R 2DEG 1 R 2DEG 2 R contact 1 R contact 2 Gate voltage dependent C QPC Wire bond ~2.2nH L kinetic 1 L kinetic 2 R QPC R 2DEG 1 R 2DEG 2 R contact 1

ABSTRACT The development of nanoscale RF circuit components is important or the development of RF readout circuitry to determine with high temporal resolution[1] the number of electrons on a quantum dot. This has applications in THz spectroscopy at the nanoscale[2] and quantum computing. In this work, we develop a realistic, physics based, practical RF circuit model for the AC impedance of a quantum point contact that includes the ohmic contacts, the on-chip "lead" resistance and kinetic inductance, and the quantum point contact impedance itself. The kinetic inductance of the electrons in the "leads" in series with the quantum point contact capacitance form a resonant tank circuit whose resonant frequency depends on the width of the quantum point contact channel. These measurements probe devices in a qualitatively new regime: They are in the ballistic limit, and the measurement frequency is higher than the electron scattering frequency. Cryostat Cryosta

Fabrication of 3-D Silicon Microneedles Using a Single-Step DRIE Process

Fabrication of 3-D microstructures is one of the most challenging aspects of silicon micromachining. In this paper, we present a novel microfabrication method using one single-step deep reactive ion etching process with gray-scale e-beam lithography mask that offers deeply etched (>350-µm deep) dual-angle 3-D microneedles with control over the height and shape of the structures. Moreover, we found that the shape of the e-beam lithography patterns can determine the general configuration and features of the final etched microneedles, and that the etching process parameters have the most impact on the microneedles’ shape, such as size and vertical base angle. Large arrays of 20 x 20 microneedles with height uniformity of better than 3% are fabricated