Anodic behavior of InP: film growth, porous structures and current oscillations.

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Buckley, D. Noel
O'Dwyer, Colm
Harvey, E.
Melly, T.
Sutton, David
Newcomb, Simon B.
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We review our recent work on the anodization of InP in KOH electrolytes. The anodic oxidation processes are shown to be remarkably different in different concentrations of KOH. Anodization in 2 - 5 mol dm-3 KOH electrolytes results in the formation of porous InP layers but, under similar conditions in a 1 mol dm-3 KOH, no porous structure is evident. Rather, the InP electrode is covered with a thin, compact surface film at lower potentials and, at higher potentials, a highly porous surface film is formed which cracks on drying. Anodization of electrodes in 2 - 5 mol dm-3 KOH results in the formation of porous InP under both potential sweep and constant potential conditions. The porosity is estimated at ~65%. A thin layer (~ 30 nm) close to the surface appears to be unmodified. It is observed that this dense, near-surface layer is penetrated by a low density of pores which appear to connected it to the electrolyte. Well-defined oscillations are observed when InP is anodized in both the KOH and (NH4)2S. The charge per cycle remains constant at 0.32 C cm-2 in (NH4)2S but increases linearly with potential in KOH. Although the characteristics of the oscillations in the two systems differ, both show reproducible and well-behaved values of charge per cycle.
KOH electrolytes , Anodic formation , Transmission electron microscopy , Anodization , Anodic oxidation , Oscillatory behavior
Buckley, D. N., O’Dwyer, C., Harvey, E., Melly, T., Sutton, D. and Newcomb, S. B. (2003) 'Anodic behavior of InP: film growth, porous structures and current oscillations', State-of-the-Art Program on Compound Semiconductors (SOTAPOCS XXXVIII) and Wide-Bandgap Semiconductors for Photonic and Electronic Devices and Sensors III, 203rd ECS Meeting, Palais des Congres de Paris, France, 27 April - 2 May. Proceedings - Electrochemical Society, Vol. 4, pp. 48-62. ISBN 1-56677-349-0.
© 2003, Electrochemical Society