We describe a simple and scalable method for the transfer of CVD graphene for the fabrication of field effect transistors. This is a dry process that uses a modified RCA-cleaning step to improve the surface quality. In contrast to conventional fabrication routes where lithographic steps are performed after the transfer, here graphene is transferred to a pre-patterned substrate. The resulting FET devices display nearly zero Dirac voltage, and the contact resistance between the graphene and metal contacts is on the order of 910 ± 340 Ω μm.

A graphene channel field-effect biosensor is demonstrated for detecting the binding of double-stranded DNA and poly-l-lysine. Sensors consist of chemical vapor deposition graphene transferred using a clean, etchant-free transfer method. The presence of DNA and poly-l-lysine are detected by the conductance change of the graphene transistor. A readily measured shift in the Dirac voltage (the voltage at which the graphene's resistance peaks) is observed after the graphene channel is exposed to solutions containing DNA or poly-l-lysine.

Graphene mechanical resonators have recently attracted considerable attention for use in precision force- and mass-sensing applications. To date, readout of their oscillatory motion typically requires cryogenic conditions to achieve high sensitivity, restricting their range of applications. Here we report the demonstration of an evanescent optical readout of graphene motion, using a scheme which does not require cryogenic conditions and exhibits enhanced sensitivity and bandwidth at room temperature.

We review recent experiments in which superfluid 3He has been studied under highly controlled confinement in nanofluidic sample chambers. We discuss the experimental challenges and their resolution. These methods open the way to a systematic investigation of the superfluidity of 3He films, and the surface and edge excitations of topological superfluids. © 2014 Springer Science+Business Media New York.

Design of high quality factor (Q) micromechanical resonators depends critically on our understanding of energy losses in their oscillations. The Q of such structures depends on process induced prestress in the structural geometry, interaction with the external environment, and the encapsulation method. We study the dominant fluid interaction related losses, namely, the squeeze film damping and acoustic radiation losses in a drumhead microresonator subjected to different prestress levels, operated in air, to predict its Q in various modes of oscillation.

We present data for the energy dissipation factor Q-1 over a broad temperature range at various pressures of a torsion pendulum setup used to study He3 confined in a 98% open silica aerogel. Values for Q-1 above Tc are temperature independent and have weak pressure dependence. Below Tc, a deliberate axial compression of the aerogel by 10% widens the range of metastability for a superfluid equal spin pairing (ESP) state; we observe this ESP phase on cooling and the B phase on warming over an extended temperature region.

The B phase of superfluid He3 is a three-dimensional time-reversal invariant topological superfluid, predicted to support gapless Majorana surface states. We confine superfluid He3 into a thin nanofluidic slab geometry. In the presence of a weak symmetry-breaking magnetic field, we have observed two possible states of the confined He3-B phase manifold, through the small tipping angle NMR response. Large tipping angle nonlinear NMR has allowed the identification of the order parameter of these states and enabled a measurement of the surface-induced gap distortion.

Resonant mechanics of high quality factor (Q) graphene coated silicon nitride devices have been explored using optical and electrical transduction schemes. With the addition of the graphene layer, we retain the desirable mechanical properties of silicon nitride but utilize the electrical and optical properties of graphene to transduce and tune the resonant motion by both optical and electrical means.

High stress stoichiometric silicon nitride resonators, whose quality factors exceed one million, have shown promise for applications in sensing, signal processing, and optomechanics. Yet, electrical integration of the insulating silicon nitride resonators has been challenging, as depositing even a thin layer of metal degrades the quality factor significantly.

A semi-analytical study of the acoustic radiation losses associated with various transverse vibration modes of a micromechanical (MEMS) annular resonator is presented. The quality factor, Q, of such resonators is of interest in many applications and depends on structural geometry, fluid-structure interaction, and the device encapsulation. Resonators with at least one surface exposed to air can display significant losses through acoustic radiation even at μm dimensions.