Method for the synthesis of an array of metal nanowire capable of supporting localized plasmon resonances and photonic device comprising said array

A method synthesizing an array of metal nanowires adapted to support localized plasmon resonances, comprising the following steps:

• a) arranging a planar substrate of dielectric material;
• b) depositing a polycrystalline metal film on the planar substrate;
• and
• c) irradiating the polycrystalline metal film with a defocused beam of noble gas ions under high vacuum, including:
• c1) producing a corrugation on a surface of the polycrystalline metal film formed by a plurality of mutually parallel nanoscale self-organized corrugations;
• c2) subsequently increasing accumulated ion doses and increasing a height of a peaks of the self-organized corrugations relative to valleys interposed therebetween;
• c3) then further increasing the accumulated ion doses and eroding the polycrystalline metal film and exposing the planar substrate at the valleys and mutually disconnecting the self-organized corrugations, generating said array of metal nanowires;
• c4) further increasing the accumulated ion doses and reducing the cross-section by reducing a longitudinal width of nanowires of the array of nanowires in a controlled manner, and adjusting a position of the localized plasmon resonances which can be associated thereto to lower wavelengths, and
• wherein, during ion irradiating, the polycrystalline metal film and the planar substrate temperature are controlled and kept below a level of decaying of the self-organized corrugations or nanowires by diffusive relaxation.