Chaos-order transitions at corroding silicon surface

Temporal patterning of the potential induced by localized corrosion of iron passivity in acid media. Growth and breakdown of the oxide film described in terms of a point defect model

“…This behavior resembles the occurrence of potential oscillations observed under galvanostatic conditions during the growth of nanotubular TiO 2 layers on titanium in fluoride-containing sulfate solutions 56 and microstructures at the Si|HF interface. [57][58][59] SEM images show unambiguously that the oscillating potential corresponds to alternating stages of oxide film growth and subsequent detachment of the oxide from the surface (Fig. 7) initiated by localized attack by chlorides.…”

Simultaneous Observation of Current Oscillations and Porous Film Growth during Anodization of InP

“…The oscillations are typically observed in the electropolishing region of the applied potential where a thin surface film is present . Evidence for the cyclic growth and dissolution of thin SiO 2 layers on the silicon surface during the oscillatory regime was also reported. , The shape, frequency, and duration of the oscillatory behavior were reported to be dependent on electrolyte composition, temperature, applied anodic current density, and crystal orientation of the substrate. Several hypotheses have been proposed, , but as yet, no general mechanism has been advanced that explains all of the reported results.…”

Modelling electrochemical current and potential oscillations at the Si electrode

“…That is also the reason why stable potential oscillations are relatively hard to obtain, as also shown indirectly by the relatively small number of published papers dealing with this topic. For high anodization currents [52,53] and an ''exotic'' electrolyte [71] not containing HF, Parkhutik found long lasting stable oscillations [72]. Lehmann investigated the potential and the oxide thickness oscillations at relatively high electrolyte concentrations [51,15].…”

“…While this mechanism is possible and might be observed under special conditions, it is not the general cause of Si electrode oscillations and moreover purely qualitative. Some related work [53] studied the nature of chaotic and ordered oscillations and invoked porous oxide formation as part of the oscillating mechanism, but remained qualitative and did not offer new insights.…”