Submicro photopatterning of alkanethiolate self-assembled monolayer using a negative mask and its application in the fabrication of biomolecular photodiode

Alkanethiolate self-assembled monolayer (SAM) formed by the adsorption of 11-mercaptoundecanoic acid (11-MUDA) molecules on a gold substrate. The alkanethiolate was oxidized by the irradiation of deep UV light with a 700-nm negative mask and then developed with a deionized water. A uniform submicro-pattern of 11-MUDA SAM was obtained. In order to array cytochrome c molecules along the patterned substrate, the well-characterized cytochrome c was immobilized. Electrochemical properties and morphology of the cytochrome c monolayer were investigated through the measurements of cyclic voltammetry and AFM. In addition, current–voltage characteristics of biomolecular multilayers consisting of cytochrome c and green fluorescent protein (GFP) were studied with a scanning tunneling microscope (STM).