A.S. Berdinsky

Stable and high emission current from carbon nanotube paste with spin on glass

We prepared carbon nanotube (CNT) pastes with different inorganic binders such as glass frit and spin on glass (SOG). MWNT powders grown by CVD were used for electron emissive source. The three-roll mill process was carried out for mixing and dispersion of CNT powders in organic vehicle as polymer matrix. CNT paste was printed onto various substrates such as an indium thin oxide (ITO) coated soda lime glass and a nickel plate. Then CNT paste was sintered under different ambient and temperature. For the analysis of the surface morphology of the cathode layer, field-emission scanning electron microscopy (FESEM) was used. The FE characteristics of CNT paste were measured in a high vacuum chamber with a parallel diode type configuration at 5/spl times/10/sup -6/ Torr. We obtained stable and high emission current from CNT paste with SOG. Our experiments have shown that CNT paste with SOG can use as efficient electron emitter in vacuum nanoelectronics such as radio frequency amplifier, field emission display and X-ray tube.

The N–P–N structure based on C60/p-Si heterojunctions

To form C60/p-Si heterojunctions, thin fullerite films were evaporated onto silicon substrates. The fullerite conductivity is anisotropic with σL ≪ σT, where σL is the lateral, and σT is the transverse conductivity with respect to the fullerite layer geometry. As a consequence, the main current from one planar contact on the surface of the fullerite film to another does not flow through the fullerite layer, but through one p–n heterojunction into the underlying silicon layer, and from there via another p–n heterojunction to the second contact – even if the contact spacing is in the order of nanometers only. In this way, a novel family of varistors and/or transistors can be created. The basic characteristics of these structures named ‘FOS’ (fullerite on silicon) are shown and explained. The strong dependence of the lateral fullerite conductivity on ambient factors such as humidity and chemical environment makes the creation of sensors possible. The combination of two C60/p-Si heterojunctions towards n–p–n structures as described here shows that fullerite is a prospective material even for nanoelectronic devices.

Fabrication and characteristics of flat lamp with CNT based triode structure for back light unit in LCD

Instead of the CVD method to form a gate oxide layer, a wet-etching method was used to form an insulating layer and isolate cathode layer from gate electrode. The wet-etching process has many advantages such as simple manufacture process, mass production and low cost. A gate triode structure was fabricated because of its simplicity in fabrication process and beam broadening. A new type of triode structure using wet-etching process was made and their field emission characteristics, uniformity and efficiency for light source for backlight units(BLU) were investigated

Creation of nanoscale electronic devices by the swift heavy ion technology

Recent years have brought a renaissance of interest in swift heavy ion track technology, for the sake of prospective novel applications, i.e. creation of nanoscale electronic devices. This paper summarizes some of the newly emerging possibilities, and the strategies that have been initiated. Only a few applications that are based on latent tracks have emerged since then, such as the exploitation of phase transitions, chemical changes, the enhanced free volume along latent tracks, or their capability to trap diffusing penetrants. For contrast, etched tracks in both polymer foils and SiO/sub 2/ layers appear to have a much greater application potential. Compact rods and tubules as well as dispersed nanosized matter can be embedded within the etched tracks, to form the base of various applications.

Study on resistance of iodine-intercalated fullerene films

A study on resistance of iodine-intercalated fullerene film has been done. Research on electro-physical properties of new materials is an important scientific and applied problem. In this work we show the technology of producing iodine-intercalated fullerene films, the construction of a resistor with iodine-intercalated C/sub 60/ fullerene film as conductive media and the results of measured resistance.

The effect of external mechanical stress on the fullerite conductivity

The possibility to use powder consisting of fullerite microcrystals as device sensitive in external mechanical load is considered. As we suppose the change of conductivity of fullerite microcrystal powder as function of environmental mechanical stress is useful for creation of nanoscale devices of sensor electronics. This new effect based on changing of intermolecular distance between fullerene molecules due to action of external mechanical force, which can change the distance between fullerene molecules because of weak van-der-Waals interaction exists. The founded effect is quite linear and sensitivity of this effect to external mechanical stress more then in well-known pressure transducers based on silicon technology.

Gas-phase technology and structure of films based on C/sub 60/ fullerene

The technology of C/sub 60/ fullerite film preparation by means of gas-phase deposition and the structure of the films are described. A flow three-channel set-up was used to obtain fullerene films. The films were deposited in an inert gas flow under reduced pressure onto a cooled silicon or sapphire substrate placed inside the reaction chamber. This set-up allows one to obtain films of pure fullerenes and to synthesise films from fullerene compounds and doped fullerenes. The film structure was investigated by FESEM and SEM techniques. All samples show columnar structure with a high level of porosity. The synthesis of fullerene-based films for use in electronics is shown to be promising. For example, experiments confirm the possibility of using fullerene films to produce humidity and thermal sensors. It is also possible to employ the sensitivity of these films to isostatic pressure. Experiments with C/sub 60/-Cu-J films shown quite strong dependence on the pressure of different sorts of medium-gases that could be used as gas-sensitive sensors. The structure and preparation technology of resistive sensors based on fullerene films are described.

Effect of electrical aging on emission stability of carbon nanotube field emitter

In this study, the effects of electrical aging on emission stability of screen-printed carbon nanotube(CNT) emitter is investigated. Results show that stable and uniform emission currents from CNT emitter are obtained during the multiple field emission cycling. During the initial stage of electrical aging, an emission current fluctuation is observed and is gradually reduced and electron emission stabilized as time passes.

Field emission properties of carbon nanotube paste on cathode with a curved surface for microwave power amplifier

In this report, we present field emission properties of the carbon nanotube (CNT) paste on cathode with a curved surface for MPA. The CNT paste was prepared using a mixture of multiwalled CNTs powders synthesized by chemical vapor deposition method, organic vehicles, and inorganic binders. We made use of both spin on glass (SOG) and a sensitizer as an inorganic binder and additive to the CNT paste. Then the paste was rubbed over a round cathode (diameter, D-4.3 mm) with a curved surface (a radius of curvature, R/spl sim/9.7 mm) designed specifically for our X-band (8-12 GHz) TWT-MPA.

Field emission properties of selectively grown carbon nanotubes for electron emitters in microwave power amplifier

We have directly grown CNTs on the metal substrates by direct-current plasma-enhanced chemical-vapor deposition (DC-PECVD) using a gas mixture of C/sub 2/H/sub 2/ and NH/sub 3/ at relatively low temperature (550 /spl deg/C). In this study, we report field emission properties of CNTs depending on pattern sizes and spacings. Field-emission characteristic of CNTs was evaluated in a vacuum of 10/sup -6/ Torr in a parallel diode configuration. It is found that there is a correlation between pattern morphologies (such as window area, spacing, and dimension of window edge, etc.) and the field-emission properties. Furthermore, we found that the contact resistance between CNTs and substrate is a crucial factor for the saturation of field emission from CNTs.