Focussed electron beam induced deposition of platinum plasmonic antennae

The direct write of photonic elements onto substrates presents opportunities for rapid prototyping and novel sensing architectures in domains inaccessible to traditional lithography. In particular, focussed electron beam induced deposition (FEBID) of platinum is a convenient technology for such direct-write applications with the advantage of relatively controlled deposition parameters and sub-10 nm resolution. One issue for FEBID of platinum is that the precursor gas contains a relatively high carbon content, which in turn leads to carbonaceous deposits in the final structure. Here we explore the creation of plasmonic nanoantennae using FEBID platinum. We compare as-deposited and annealed antenna with heights of 40 nm and 56 nm, showing the effect of annealing on the carbon concentration and hence the optical properties. These results are compared with modelling using Mie scattering theory. Our results show that FEBID platinum is a useful material for the direct-write of plasmonic nanoantenna.