Jacek Tyczkowski

Modification of styrene-butadiene rubber surfaces by plasma chlorination

Abstract Chlorination with halogenating agents in organic solutions is a common surface treatment for styrene–butadiene rubber materials to improve their adhesion to polyurethane adhesives. An attempt to replace this wet chemical method with a clean plasma technique has been undertaken. Styrene–butadiene rubbers (both model elastomers, such as Finaprene 435 and Finaprene 507 and a typical composite vulcanised rubber) were exposed to the action of plasma generated in various reactive mixtures containing chlorine moieties. As chlorine precursors, trichloromethane (CHCl3), tetrachloromethane (CCl4), and chlorine (Cl2) were used. These compounds were supplied to the reactors as a pure agent or in a mixture with argon or oxygen. Pure argon and air were also tested. The process was performed both in RF (13.56 MHz) and AF (20 kHz) glow discharges, utilising electrode reactors working at low pressure. FTIR spectroscopy, contact angle measurements, and T-peel tests (before and after plasma treatment) characterised the elastomer surfaces. It has been found that for the pure CHCl3 and CCl4 plasmas with a relatively low power, the peel strength of the treated rubber surfaces is approximately 56% higher than that for the materials chemically chlorinated, and two to three times higher in comparison with the non-treated surfaces.

Deposition technology of a new nanostructured material for reversible charge storage

Abstract Reversible charge storage effect was observed in thin amorphous hydrogenated carbon-germanium films produced by plasma enhanced chemical vapor deposition. These films consist of semiconductor grains embedded in an insulator matrix. The grains could serve as charge containers separated from one another by insulator walls. Scanning probe microscope equipped with conducting tip and cantilever is utilized for both local charge imaging and its modification. Depending on the sign of voltage applied to the tip, charge can be locally injected or removed from the film. Exploring this technique in data storage application, one can achieve information density of the order 1014 bit/m2.

Amorphous semiconductor and amorphous insulator : two kinds of hydrogenated carbon-silicon films fabricated in the three-electrode reactor

Abstract Amorphous hydrogenated carbon–silicon (a-Si X C Y :H) films were produced by plasma-enhanced chemical vapor deposition (PECVD) in an audio-frequency (a.f.) three-electrode reactor using tetramethylsilane as a source compound. The negative amplitude of a.f. voltage, V (−) , measured on a small electrode, on which the films were deposited, with respect to the ground was the only operational parameter of the deposition process. Investigations on electrical conductivity, optical absorption and internal photoemission were carried out. It has been found that a rapid transformation in the electrical conductivity occurs when V (−) changes from 600 to 750 V (from 10 −16 to approx. 10 −8 S/m). This effect has been attributed to the amorphous insulator–amorphous semiconductor transition, which is controlled in this case by a percolation process.

Amorphous covalent dielectrics-new category of materials

The concept of amorphous covalent dielectrics is presented. It is shown that plasma-deposited Si-C and Ge-C films exist in two qualitatively different groups. The first group consists of typical amorphous semiconductors while the second one is categorized as amorphous dielectrics. The most important feature distinguishing one group from another is the lack of extended states in the dielectrics.

Electron-beam-pulse induced time-domain depolarization in plasma deposited hydrogenated carbon-silicon films

In this paper an interesting extension of the VPITDD in the domain of shorter polarization times is presented. The results for plasma deposited carbon-silicon films are discussed in details.

Voltage-pulse induced time-domain depolarization for plasma-deposited organosilicon films

Measurements of the voltage-pulse-induced time-domain depolarization (VPITDD) were used to investigate plasma polymerized organosilicon films. It was found that the observed relaxations were related to bulk processes. A two-center model was proposed to describe this phenomenon. Poole-Frenkel centers and traps lying near the Poole-Frenkel energy level were attributed to the observed relaxations.<<ETX>>