Résumé
We investigate highly doped InAsSb layers grown by molecular beam epitaxy on GaSb substrates. Electrical and optical characterizations demonstrate a metallic behavior with the possibility to control the plasma frequency in the mid-infrared range by adjusting the doping level. Plasmonic resonators based on this new kind of metal can be realized for mid-IR applications. Sub-wavelength periodic arrays are fabricated in the InAsSb layer and localized surface plasmon resonances are observed in reflectance experiments. A perfect control of the doping level and of the geometry of the periodic arrays allows adjusting the frequency of the plasmonic resonances. Our work shows that GaSb-based materials could be the building block for all-semiconductor mid-infrared plasmonic devices.