This experiment is designed to expose undergraduate students to the process of selective etching by using soft lithography and the resulting electrical properties of multilayered films fabricated via self-assembly of gold nanoparticles. Students fabricate a conductive film of gold on glass, apply a patterned resist using a polydimethylsiloxane stamp, and etch the unprotected gold. The resulting pattern is evaluated for changes in current, voltage flow, and resistance relative to the initial properties of the nonetched films. Students determine how changes in resistance applied to a conductive pattern affect the flow of current and voltage. Comparisons are made among different electrolyte solutions to demonstrate the electrical difference between strong, weak, and nonelectrolyte solutions, and how stronger electrolytes provide for better current flow.
Supplement
Experimental details, including a list of materials, equipment, and chemicals; Instructions for preparing the solutions, fabricating the conductive films, fabricating the polydimethylsiloxane (PDMS) stamp, and configurations of the jumper wiring for varying measurement setups
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