Plasmonic switching in Au functionalized GaN nanowires in the realm of surface plasmon polatriton propagation: A single nanowire switching device

摘要

Photoresponse of Au nanoparticle functionalized semiconducting GaN (Au-GaN)nanowires is reported for an optical switching using 532 excitation. Wide bandgap GaN nanowires are grown by catalyst assisted chemical vapour depositiontechnique and functionalized with Au in the chemical route. Au-GaN nanowiresshow surface plasmon resonance (SPR) mode of Au nanoclusters around 550 nmalong with characteristic band for GaN around 365 nm. An optical switching isobserved for Au-GaN nanowires with a sub-band gap excitation of 532 nmsuggesting possible role of surface plasmon polariton assisted transport ofelectron in the system. Role of band conduction is ruled out in the absence ofoptical switching using 325 nm excitation which is higher in energy that thereported band gap of GaN about 3.4 eV (365 nm) at room temperature. A finiteamount of interband contribution of Au plays an important role along with theinter-particle separation. The switching device is also successfully tested fora single GaN nanowire functionalized with Au nanoclusters. A resistivity valueof 0.05 Ohm-cm is measured for surface plasmon polariton assisted electricaltransport of carrier in the single GaN nanowire.