COMBINING MICROMACHINING AND MOLECULAR SELF-ASSEMBLY TO FABRICATE MICROELECTRODES

This paper describes three types of gold electrodes, each with at least one spatial dimension as small as 1 mum, fabricated using combinations of micromachining and molecular self-assembly. (i) Large-area (>0.1 MM2) arrays of band-type electrodes were formed by machining micrometer-wide grooves of bare gold into gold film covered with a approximately 23-angstrom-thick, electrically insulating, self-assembled monolayer (SAM) of CH3(CH2)15S. (ii) Micrometer-wide, centimeter-long, 100-nm-thick gold electrodes supported on glass were fabricated by patterning a gold film with monolayers of CH3(CH2)15S and HO(CH2)2S, and selectively etching the regions of gold covered with HO(CH2)2S using an aqueous solution of CN- saturated with 02. (iii) Two microelectrodes, each with electrochemically active areas as small as 100 nm x 1 mum and separated from each other by a distance of lum, were formed by machining a 1-mum-wide gap into a supported gold wire covered with an electrically insulating SAM of CH3(CH2)15S; exposed gold on either side of the machined gap formed the electrochemically active surfaces of the microelectrode pair.