Programmable definition of nanogap electronic devices using self-inhibited reagent depletion.
Electrodes exhibiting controlled nanoscale separations are required in devices for light detection, semiconductor electronics and medical diagnostics. Here we use low-cost lithography to define micron-separated electrodes, which we downscale to create three-dimensional electrodes separated by nanoscale gaps. Only by devising a new strategy, which we term electrochemical self-inhibited reagent depletion, were we able to produce a robust self-limiting nanogap manufacturing technology. We investigate the method using experiment and simulation and find that, when electrodeposition is carried out using micron-spaced electrodes simultaneously poised at the same potential, these exhibit self-inhibited reagent depletion, leading to defined and robust nanogaps. Particularly remarkable is the formation of fractal electrodes that exhibit interpenetrating jagged elements that consistently avoid electrical contact. We showcase the new technology by fabricating photodetectors with responsivities (A/W) that are one hundred times higher than previously reported photodetectors operating at the same low (1-3 V) voltages. The new strategy adds to the nanofabrication toolkit method that unites top-down template definition with bottom-up three-dimensional nanoscale features.
Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada.
Brian
B
Lam
Department of Electrical and Computer Engineering, Faculty of Engineering, University of Toronto, Toronto, Ontario M5S 3M2, Canada.
Wendi
W
Zhou
1] Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada [2] Department of Chemistry, Faculty of Arts and Sciences, University of Toronto, Toronto, Ontario M5S 3M2, Canada [3] Institute for Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3M2, Canada [4] Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 3M2, Canada.
Shana O
SO
Kelley
Department of Electrical and Computer Engineering, Faculty of Engineering, University of Toronto, Toronto, Ontario M5S 3M2, Canada.
Edward H
EH
Sargent