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We have performed detailed analysis of the fluctuations of the electrical current in electrochemically deposited conductive polymers (CP) using as example polyaniline and poly(3methylthiophene). These heterogeneous and disordered materials cannot be analyzed in terms of classical conduction mechanisms (like Schottky or Poole-Frenkel emission). Instead, the electrical transport in CPs is to be considered as a stochastic process with large component of noise. We have been able to distinguish several modes of the conduction process in CPs by applying Flicker Noise Spectroscopy. Thus, we have established that the transport of charge carriers in highly doped CPs is much less correlated than in non-doped ones at the same electric field strength. While applied electric field increases, correlations become lower in a sequence of elementary events contributing to the conductivity of CP. Apparently, the change in the correlation length corresponds to changing mechanism of the electrical conduction. The lower correlation in highly doped sample can be attributed to various factors including change in CP conformation, enhancement in interchain charge transfer and generation of polaron lattice.

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In a series of recent works performed at the R&D Centre MTM we have registered and analysed quite intriguing effects of oscillating current and voltage during silicon electrochemical treatments in fluoride-containing electrolytes. Depending on the experimental conditions the oscillations can exhibit an amplitude from milliVolts to 20-60 Volts and periods from 0.2 to 200 seconds. They are quite sensitive to the temperature of solution, electrolyte stirring, concentration of acid, sample history, periodic external impact, etc. In each particular case there is a coupling between different parallel electrochemical reactions that gives rise to the oscillatory behaviour.We discuss general conditions for the occurrence of the oscillations of current or voltage in a system Si/electrolyte and show that this case is described by the same phenomenological laws as other cases of chaos-order transitions (f.i. Belousov-Zabotinsky reactions) though in the present case reaction products and variables are very different from other existing oscillatory systems. Through studying the oscillatory processes at corroding Si electrode we can get a general information which is useful in studying other chemical and physical processes that yield similar behaviour.