K. Adlkofer et al., Electrochemical passivation of gallium arsenide surface with organic self-assembled monolayers in aqueous electrolytes, APPL PHYS L, 76(22), 2000, pp. 3313-3315
Self-assembled monolayers of octadecylthiol (ODT) were reconstituted on fre
shly etched gallium arsenide (n-GaAs) for the electrochemical stabilization
against decomposition of the surfaces (passivation) in aqueous buffers. Th
e surface composition was evaluated by x-ray photoelectron spectroscopy to
optimize the surface treatment before ODT deposition. Electrochemical prope
rties of the monolayers were monitored by cyclic voltammetry and impedance
spectroscopy. The impedance spectrum of the photoetched n-GaAs after the de
position of the ODT monolayer was stable in an aqueous electrolyte at pH=7.
5 for more than 24 h within the sensitivity of our experimental technique.
The effective passivation of GaAs surfaces is an essential step towards bio
sensor applications. (C) 2000 American Institute of Physics. [S0003-6951(00
)01422-4].