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Formation of nanoporous InP by electrochemical anodization
Buckley, D. Noel; O'Dwyer, Colm; Lynch, Robert P.; Newcomb, Simon B.
Porous InP layers can be formed electrochemically on (100) oriented n- InP substrates in aqueous KOH. A nanoporous layer is obtained underneath a dense near-surface layer and the pores appear to propagate from holes through the near-surface layer. In the early stages of the anodization transmission electron microscopy (TEM) clearly shows individual porous domains which appear to have a square-based pyramidal shape. Each domain appears to develop from an individual surface pit which forms a channel through this near-surface layer. We suggest that the pyramidal structure arises as a result of preferential pore propagation along the <100> directions. AFM measurements show that the density of surface pits increases with time. Each of these pits acts as a source for a pyramidal porous domain. When the domains grow, the current density increases correspondingly. Eventually, the domains meet forming a continuous porous layer, the interface between the porous and bulk InP becomes relatively flat and its total effective surface area decreases resulting in a decrease in the current density. Numerical models of this process have been developed. Current-time curves at constant potential exhibit a peak and porous layers are observed to form beneath the electrode surface. The density of pits formed on the surface increases with time and approaches a plateau value.
Keyword(s): Porous InP layers; InP substrates; Aqueous KOH; Transmission electron microscopy (TEM); AFM measurement; Electrochemistry; Materials science
Publication Date:
2004
Type: Conference item
Peer-Reviewed: Yes
Language(s): English
Institution: University College Cork
Citation(s): Buckley, D. N., O’Dwyer, C., Lynch, R., Sutton, D., Newcomb, S. B. (2004) 'Formation of Nanoporous InP by Electrochemical Anodization', 206th Meeting of the Electrochemical Society: State -of-the-Art Program on Compound Semiconductors XLI. Hilton Hawaiian Village, Honolulu, Hawaii, 3-8 October. Pennington, NJ: The Electrochemical Society, 6, pp. 103-117.
Publisher(s): The Electrochemical Society
File Format(s): application/pdf
First Indexed: 2013-03-05 05:30:50 Last Updated: 2016-10-14 06:29:44