We report on the preparation and field emission properties of quasi-aligned silicon carbon nitride ͑SiCN͒ nanorods. The SiCN nanorods are formed by using a two-stage growth method wherein the first stage involves formation of a buffer layer containing high density of nanocrystals by electron cyclotron resonance plasma enhanced chemical vapor deposition and the second stage involves using microwave plasma enhanced chemical vapor deposition for high growth rate along a preferred orientation. It should be noted that growth of the SiCN nanorods is self-mediated without the addition of any metal catalyst. Scanning electron microscopy shows that the SiCN nanorods are six-side-rod-shaped single crystals of about 1-1.5 m in length and about 20-50 nm in diameter. Energy dispersive x-ray spectrometry shows that the nanorod contains about 26 at. % of Si, 50 at. % of C, and 24 at. % of N. Characteristic current-voltage measurements indicate a low turn-on field of 10 V/m. Field emission current density in excess of 4.5 mA/cm 2 has been observed at 36.7 V/m. Moreover, SiCN nanorods exhibited rather stable emission current under constant applied voltage.

Noise characteristics of emission current from conductive diamond-like carbon thin films coating on cone shaped silicon field emitters Ultrathin carbon layers with thicknesses below 50 Å have been deposited on silicon microtip arrays by bias-assisted carburization ͑BAC͒ using microwave plasma chemical vapor deposition. The tip radius of these silicon tips is reduced below 55 nm under low deposition temperature. The field emission characterization has been performed in a high-vacuum environment. An enhancement in the field emission is observed of about 3 orders of magnitude in BAC silicon microtips over untreated silicon microtips. With an applied voltage of 1100 V, emission currents of 80 and 120 A have been achieved for the films grown ͑at dc bias of Ϫ200 V for 40 min͒ with 15% and 25% CH 4 /H 2 gas ratio, respectively. An emission current of 40 A has been achieved for the film grown ͑at dc bias of Ϫ300 V for 40 min͒ with 3.5% CH 4 /H 2 ratio. The BAC silicon emitter has good emission stability at a constant voltage of 1100 V. These investigations indicate that further improvement of this technology will lead to simple and inexpensive field emission display devices.

Collective emission degradation behavior of carbon nanotube thin-film electron emittersArrays of carbon nanotubes ͑CNT͒ and diamond-clad Si tips were grown by microwave plasma-enhanced chemical vapor deposition. The former ones were grown directly on prepatterned cobalt-coated silicon substrate, while the latter ones were grown on Si-tip arrays. Each array contains 50ϫ50 emitting cells and each individual cell is 3 m square. A maximum effective emission current density of about 17 A/cm 2 ͑at a macroscopic field of 17.5 V/m͒ has been demonstrated, while a macroscopic emission current density of 10 mA/cm 2 with operating fields around 10 V/m can be routinely achieved from an array of CNT emitters. In contrast, operating fields above 20 V/m were needed to draw a comparable emission current density from all of the diamond-clad Si tips arrays. Emission stability test performed at 40 mA/cm 2 for CNT arrays also showed little sign of degradation. Due to the high efficiency of electron emission, simple sample process, and large area growth capability, field emitter arrays based on CNT are attractive for flat panel display applications.

A central challenge in gravitational wave astronomy is identifying weak signals in the presence of non-stationary and non-Gaussian noise. The separation of gravitational wave signals from noise requires good models for both. When accurate signal models are available, such as for binary Neutron star systems, it is possible to make robust detection statements even when the noise is poorly understood. In contrast, searches for 'un-modeled' transient signals are strongly impacted by the methods used to characterize the noise. Here we take a Bayesian approach and introduce a multi-component, variable dimension, parameterized noise model that explicitly accounts for non-stationarity and non-Gaussianity in data from interferometric gravitational wave detectors. Instrumental transients (glitches) and burst sources of gravitational waves are modeled using a Morlet-Gabor continuous wavelet frame. The number and placement of the wavelets is determined by a trans-dimensional reversible jump Markov chain Monte Carlo algorithm. The Gaussian component of the noise and sharp line features in the noise spectrum are modeled using the BayesLine algorithm, which operates in concert with the wavelet model.

A new field emission device composed of carbon nanotubes and a thin film transistor ͑TFT͒ has been successfully demonstrated to significantly improve emission stability. Carbon nanotubes are directly integrated in the drain region of the TFT and the emission current from the carbon nanotubes is controlled via the TFT drain current. The fluctuation of the emission current of the TFT-controlled carbon nanotubes can be suppressed to less than 2%, below the fluctuation of uncontrolled carbon nanotubes. The novel field emission device exhibits low-voltage controllability, good emission stability, and structural simplicity, making it promising for application to future field-emission display.Field emission devices have been extensively studied to apply in sensors, microwave power amplifiers, scanning tunneling microscopes ͑STMs͒, microsized intense electron sources, and field emission displays. 1-4 While a significant amount of research has focused on triode-type field emitters, emission current stability remains a central problem in commercializing field-emission devices. An effective way to improve current stability is to connect a constant electron source, such as a field-effect transistor ͑FET͒ or thin-film transistor ͑TFT͒, to the emitters in series. 5,6 However, the process of conventional triodes combined with the FET is more complicated and the driving voltage is still high. Recently, carbon nanotubes have demonstrated excellent field emission properties for future field emission displays, due to their low electric field emission, high chemical stability, and high mechanical strength. 7-9 However, emission current fluctuation from carbon nanotubes is always observed and achieving the triode-type structure of carbon nanotubes is difficult. Song has developed an active-controlled diode emitter ͑ACDE͒ structure which significantly improves the current stability of carbon nanotubes. 10 Nevertheless, the operation of Song's design is complicated. For example, the TFT devices and carbon nanotubes were fabricated on different substrates and the drain of the TFT was connected to the cathode, i.e., the carbon nanotubes, using micromanipulators.This study proposes and fabricates a field-emission device based on monolithic TFT-controlled carbon nanotubes. The structure is simple, with the carbon nanotubes being directly synthesized on the drain region of a TFT. Meanwhile, electrons emitted from the carbon nanotubes are supplied through the inversion layer, which is produced by the field effect of a gate voltage. The TFT was designed to exhibit a high-breakdown voltage and low leakage current in the off state. The actively TFT-controlled carbon nanotubes can achieve excellent emission stability and modulation of the emission current. Figure 1 schematically illustrates the fabrication procedures of TFT-controlled carbon nanotubes. A 500 nm thick silicon dioxide was thermally grown on an n-type Si͑100͒ substrate at 1050°C. A 200 nm thick amorphous silicon ͑␣-Si͒ layer was then deposited on the thermal oxide by low-pressure c...