A.G. Kolosko

Statistical dispersion of the field emission parameters of multipoint cathodes based on a polymer-carbon nanotube composite

Statistical properties of the characteristics of a field-electron emitter based on a polystyrene-carbon nanotube composite have been studied. Experimental data have been used to plot the slope versus intercept of I-U curve in the Fowler-Nordheim coordinates and a histogram of the effective heights of emission centers. Numerical estimations show that this statistics obeys the lognormal distribution law. A series of experiments have been performed for determining the influence of the level of emission current on the character of distribution, and a model describing this dependence is proposed.

Hysteresis phenomenon of the field emission from carbon nanotube/polymer nanocomposite

Using the high voltage scanning method and the technique of multichannel recording and processing of field emission (FE) characteristics in real time mode we found out some subtle effects on current voltage characteristics (IVC) of the multi-tip field emitters. We observed the direct and reverse hysteresis simultaneously in the same field emission experiment. Dependence of the form of IVC hysteresis on time of high voltage scanning was observed.

Development of on-line emission parameters processing research technique of polymer-MWCNT emitters

The technique of record and in situ processing of data about evolution of multiwall carbon nanotubes polymer (MWCNT-polymer) field emitters was developed. It includes multichannel data acquisition system of current, voltage, vacuum level and temperature and computer on-line processing of these data by program which was written on LabView. We gained time dependence of field enhancement factor, height and number of emission sites, slope-interception diagram and voltage-current characteristics derivative.

Extracting formal emission area by on-line processing of current-voltage data, using FN-type equations for the Schottky-Nordheim barrier

We have implemented experimental methods for determining emission area parameters by using online processing of current-voltage characteristics (IVC). We calculated the formal emission area for each experimental IVC: for a single tungsten emitter and for several multi-tip emitters based on CNT and graphene. Voltage dependence in emission area is observed.

Application of slope-intercept diagram to determine the parameters of the nanocomposite field emitters in-situ

The method of the field emission data online processing of materials, perspective for a nanoelectronics, is developed. The method is based on the slope-intercept diagram analysis of the current voltage characteristics registered during the experiment. It allows to build calibration grids of the microscopic emission parameters, such as work function, effective emission area and field enhancement factor, and and to estimate changes in the sample structure online.

Emission structure stability investigation in alternating and reverse polarity electrical fields

Structure stability of a multiwall carbon nanotube - polystyrene nanocomposite was investigated in two operational modes. Statistical analysis of the emission parameters of the whiskers formed on the anode surface during field emission was carried out. The histograms of the statistical distribution of effective heights at different current levels were plotted. Mass-spectrometry data in alternating electrical fields show the presence of C2H2, H2 and CO in spectra.

Field emission and gases desorbtion of MWCNT emitters

The experimental results of polymeric nanocomposite emission characteristic dynamics and vacuum level deviation interrelation are presented. It is shown that there are distinctive values of the emission current defining further course of emission. The nanocomposite emission dynamic behavior is explained by the contribution of thermal emission and influence of adsorption-desorption processes.

Research of the polymer-MWCNT emitters in AC power supply

AC high voltage power supply impacts the emission stability of carbon polymeric nanocomposite. It is shown that threshold values of an electric field in the bipolar mode, related to the material transfer beginning from one electrode to another, are determined by the polymeric compound used in the nanocomposite emitter.

Current-voltage characteristic hysteresis dependence on power supply regime for large area field emitters

We investigated the hysteresis phenomenon in current-voltage characteristics of multipoint emitters based on nanocomposites with carbon nanotubes and graphene. The conditions under which the change in shape of the hysteresis from “direct” to “reverse” or vice versa occurs were found. Mass-spectrometer data allowed to associate hysteresis with adsorbed particles a source of which is the anode.

The technique of online analysis of the current-voltage characteristics of nanocomposite field emitters using the SK-charts

In the presented work, a new method of online processing of emission data is reported that allows us to estimate work function and geometrical parameters of the field nanostructures. The method is based on analysis of the Seppen-Katamuki chart for the current-voltage characteristics, which allows the construction of a calibration grid. Using this method, field emission characteristics of nanocomposites, with CNT and graphene as filler, were analyzed in various operating conditions.