Fabrication of nanoelectrodes and nanojunction hydrogen sensor

A simple method to fabricate nanoelectrodes with controllable gap was demonstrated by local electrical melting of nickel nanowire. The width of nanogap was tuned by diameter of nanowire and the gap distance was controlled by voltage sweep rate. These nanoelectrodes were then electrochemically backfilled with palladium to fabricate hydrogen nanojunction sensor. Sensors showed excellent sensing performance (dynamic range from 0.1% to 4% H-2 and <1 min response time for H-2 concentration > 2%) at room temperature. Our method of electrochemically backfilling a nanogap opens up a possibility to create various nanojunction devices in a cost- effective matter. (C) 2008 American Institute of Physics.