Nanotechnology and nanomaterials

Influence of the current-carrying phase dispersity on the electrophysical parameters of nanocomposites on the basis of "glass – Ru compounds"
Lepikh Ya.I., Lavrenova T.I., Sadova N.M., Zatovs’ka N.P., Nitsuk Yu.M.
Interdepartmental Scientific and Educational Physical and Technical Center of the Ministry of Education and Science of Ukraine and the National Academy of Sciences of Ukraine at the Odesa I.I. Mechnikov National University, Dvoryanska str., 2, Odesa-65082, Ukraine. E-mail:ndl_lepikh@onu.edu.ua

There are known experimental data on the electrical conductivity of binary compositions, however, the dependence of the electrical conductivity of the sintered powder compositions on the conductive components dispersion is not established. At the same time, it would be important to have the ability to change the electrophysical parameters of composite materials by changing the dispersion of the conductive phase. This is important, especially for the formation of elements of hybrid integrated circuits and microelectronic sensors. At present, there are technologies that allow the production of powders with particle sizes up to tens of nm. Therefore, the influence of the agglomerate RuO2 sizes (with fixed glass particle sizes) on the electrophysical characteristics of the "glass-RuO2" heterophase system has been investigated. The morphology and particle sizes of the powders were determined using an transmission electron microscope TEM 100-01 with an X-ray diffractometer DRON UM-1. The content of ruthenium dioxide and the constant binding in the starting pastes varied and consisted of: RuO2 - 10-50 wt. % and glass - 90-50 wt. %. Investigations have shown that the starting powder RuO2 consists of bulk agglomerates with a diameter of ~ 6 μm to 2.5 μm containing RuO2 single crystals of size ~ 50 nm. The objects of investigations were thick films, made on the basis of lead-borosilicate glass with fixed sizes of glass particles (0, 5 microns) and functional material RuO2. Composition of organic binder - ethylcellulose, terpeneol and butyl carbitol acetate. Resistive films were prepared by annealing paste deposited on aluminosilicate ceramicsVT-24 at a temperature of 8700 C, at maximum temperature of 15 minutes.
Further, the specific surface resistance ρs of annealed thick-film resistors at various sizes of RuO2 agglomerates has been investigated. The dependence ρs on the concentration ratio of glass: RuO2 and the average size of the functional material agglomerates is shown in Figure 1. The size of the glass particles is fixed (0.5 μm).

Fig. 1. The dependence of the specific surface resistance ρs on the average size of the RuO2 agglomerates and the concentration ratio of the glass: RuO2

Conclusions
Reducing of the RuO2 agglomerates average size (with a fixed glass particle sizes) leads to an increase in the specific surface resistance of the heterophase system "glass - RuO2" for all ratios of glass: RuO2 (from 10 to 50% RuO2) concentrations.
These results can be used to create hybrid integrated circuits and microelectronic sensors for different purpose of application.