Pitting and porous layer formation on n-InP anodes

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O'Dwyer, Colm
Buckley, D. Noel
Serantoni, M.
Sutton, David
Newcomb, Simon B.
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Electrochemical Society
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Surface pitting occurs when InP electrodes are anodized in KOH electrolytes at concentrations in the range 2 - 5 mol dm-3. The process has been investigated using atomic force microscopy (AFM) and the results correlated with cross-sectional transmission electron microscopy (TEM) and electroanalytical measurements. AFM measurements show that pitting of the surface occurs and the density of pits is observed to increase with time under both potentiodynamic and potentiostatic conditions. This indicates a progressive pit nucleation process and implies that the development of porous domains beneath the surface is also progressive in nature. Evidence for this is seen in plan view TEM images in which individual domains are seen to be at different stages of development. Analysis of the cyclic voltammograms of InP electrodes in 5 mol dm-3 KOH indicates that, above a critical potential for pit formation, the anodic current is predominantly time dependent and there is little differential dependence of the current on potential. Thus, pores continue to grow with time when the potential is high enough to maintain depletion layer breakdown conditions.
Atomic force microscopy , Cyclic voltammetry , Porous materials , Silicon , Transmission electron microscopy , Cyclic voltammograms , Photonic crystals , Pit formation , Porous layer formation
O'Dwyer, C., Buckley, D. N., Serantoni, M., Sutton, D. and Newcomb, S. B. (2003) 'Pitting and Porous Layer Formation on n-InP Anodes', State-of-the-Art Program on Compound Semiconductors XXXIX and Nitride and Wide Bandgap Semiconductors for Sensors, Photonics, and Electronics IV - Proceedings of the International Symposium; Orlando,FL; United States; 12-17 October, in Proceedings - Electrochemical Society, Vol. 11, pp. 136-151. ISBN 1-56677-391-1
© 2003, Electrochemical Society