CHEMISTRY
Silver Filament Formation at Nanogaps Formed from Electrodeposited Silver Nanowires.
CAMERON CAMPBELL*, NIDHI SHAH, and FRANCIS P. ZAMBORINI
Department of Chemistry, University of Louisville, Louisville KY 40292
Metal nanowire and filament research is a field of study with significant practical
applicability. Metallic filaments are often described as atomic extensions of a parent metal sheet
which can be lengthened and contracted at specific voltages.1 Due to their unique properties,
some researchers have studied how nanowires may be used in molecular sensing for toxic
molecules like hydrogen sulfide (H2S).2 Others have looked to how filaments can be used as
resistive switches in electronic components; certain voltages can switch a circuit device from a
high resistance state to a low one by growing and retracting metal filaments.3 Filaments are
desirable in these cases. In other scenarios, it would be beneficial to prevent filament formation.
One may wish to study how to halt filament formation in batteries to circumvent short circuiting.
Therefore, it is of great importance to study the nature of these filaments—how they form, break,
and respond under a set of conditions.
Here we outline the use of electrochemical oxidation and reduction reactions to form
silver metal filaments on gold interdigitated array (IDA) electrode devices in order to study
filament behavior.4 IDAs are ideal for these studies because they are simple to prepare and allow
for rapid trials and setup modification. We also studied the effect of alkanethiol self-assembled
monolayers on filament behavior. We found that filament formation may be promoted and
removed by a specific threshold voltage (switching behavior) and formation may be resisted by
self assembly of alkanethiol monolayers at the gold electrode or silver nanowire.
References:
1) Jo, S.; Lu, W. CMOS Compatible Nanoscale Nonvolatile Resistance Switching Memory.
Nano Letters. 2008, 8, 392-397.
2) Mai, L.; Xu, L.; Gao, Q.; Han, C.; Hu, B.; Pi, Y. Single β–AgVO3 Nanowire H2S Sensor.
Nano Letters. 2010, 10, 2604-2608.
3) Jo, S.; Kim, K.; Lu, W. Programmable Resistance Switching in Nanoscale Two-Terminal
Devices. Nano Letters. 2009, 9, 496-500.
4) Dasari, R.; Zamborini, F. Electrochemical Fabrication of Metal/Organic/Metal Junctions for
Molecular Electronics and Sensing Applications. Langmuir. 2011, 27, 2785-7293.