Z. Ya. Kosakovskaya

Thin films consisting of carbon nanotubes as a new material for emission electronics

The investigation results for the emission characteristics of thin films composed of nanotube carbon structures are described. These films are shown to provide high field electron emission and substantial thermal electron emission even at low temperatures. They exhibit low electron work functions and ensure stable field emission under conditions of operating vacuum.

Influence of external factors on electron field emission from thin‐film nanofilament carbon structures

The influence of temperature and residual gas pressure on the field emission of thin‐film nanotube carbon structures has been studied. These structures are shown to exhibit low work functions. They are promising for fabrication of effective low‐voltage field emitters and low‐temperature thermal emitters.

Measurement of the elastic moduli of dense layers of oriented carbon nanotubes by a scanning force microscope

A technique is developed for measuring the modulus of elasticity of a material with a Nanoscan scanning force microscope on the basis of measuring the dependence of probe vibration frequency on the penetration depth of the needle into the specimen. This technique makes it possible to study materials with elastic moduli from 50 to 1000 GPa. The Young moduli of dense films of carbon nanotubes oriented at angles of 45° and 90° to the quartz substrate are measured. From their ratio, the Young modulus in the direction perpendicular to the tubes and the anisotropy of the elastic moduli are determined. A comparison of these values with the corresponding values obtained for a nanotube film deposited on a silicon substrate is carried out. On the basis of this comparison, a conclusion is made concerning the interaction between single-layer nanotubes and between nanotubes in a mixture of single-layer and multilayer ones.

Optoacoustic effect in dense layers of oriented carbon nanotubes: Its use for measuring the optical absorption coefficient and the film thickness

The optoacoustic effect is used to measure the coefficient of light absorption at a wavelength of 0.53 μm by a dense layer of oriented carbon nanotubes on a quartz substrate. The value of the absorption coefficient is found to be equal to 3 × 106 m−1. This value is compared with the theoretical estimates and the estimate obtained from the reflection coefficient with the use of the Kramers-Kronig relation. With the coefficient of light absorption being known, the optoacoustic effect allows one to measure the film thickness at any point without destroying the film.

Acoustic and acoustoelectronic properties of carbon nanotube films

The effect of spontaneous nanotube doping by substrate atoms was discovered using acoustic resonator microwave spectroscopy. The acoustoelectric effect involving surface acoustic waves was observed in nanotube films. The possibility of using nanotube films for efficient acoustic-wave excitation in solids by electrostriction was analyzed.

Acoustic and acoustoelectron properties of carbon nanotube films

The effect of selfdoping of nanotubes by atoms from the substrate that was discovered using the BAW spectroscopy method. SAW acoustoelectric effect measurements in carbon nanotubes have been made. Detailed analysis of the possibility of the use of electrostrictive forces for the excitation of acoustic waves in solids is given. High excitation efficiency may be achieved due to the increase in the electric field near the electrodes made of the nanotube thin films.

Microwave HBAR spectroscopy and transducer application of carbon nanotube films

The BAW spectroscopy method for the acoustic characterization of carbon nanotubes was applied. The material density and the elastic constants for carbon nanotube films were evaluated directly. The effect of the increase in the electric field near the electrodes with nanotube thin films may be conveniently used in electrostatic transducers for acoustic wave excitation in nonpiezoelectric solids and liquids.

Carbon nanotube structures-a new material of vacuum microelectronics

The presented results prove that carbon nanotube structures can serve as a new material for vacuum microelectronics being highly effective emitters.

Elastic properties of dense nanotube layers

The Young modulus of a thin layer consisting of densely packed carbon nanotubes oriented normally to a substrate is measured using a scanning probe atomic force microscope. It is found that the adhesion of the film and the silicon substrate is not very strong, and, at certain conditions, this may lead to an intense energy dissipation in an oscillatory system loaded by the film.

Work function estimate for electrons emitted from nanotube carbon cluster films

Relying on the obtained theoretical and experimental results the electron work function from the nanotube carbon film was estimated. It was shown that these structures have a low work function, substantially lower than for graphite. Under estimation we regarded the influence of the film surface relief on its emission ability.