Tunable hyperbolic multilayer metamaterials as biosensors for cancer biomarker detection

There is currently a rapidly growing worldwide interest in hyperbolic metamaterials (HMM), a class of metamaterials (media with negative refractive index) characterised by hyperbolic dispersion. There are two ways to realise hyperbolic metamaterials: a multilayer composite (i.e. nanolaminates) composed of alternating metal-dielectric layers, and a structure composed of metal nanowires embedded in a dielectric matrix. Nanolaminates are composite layers produced by depositing layers of different materials of a given thickness on a substrate. The design, fabrication and development of new nanomaterials for photonic devices such as optical biosensors is an extremely important challenge of modern science and advanced technologies compared to conventional micro- and nanoelectronic devices. Optical biosensors are attractive because of their small size, light weight or mobility. In addition, these devices do not require electrical power and have high detection accuracy and precision. The performance of nanomaterials used for optical biosensors is mainly related to the high surface-to-volume ratio. The high specific surface area, its functionality, porosity, topography and morphology significantly improve the detection capacity of the sought material (e.g. analyte) as well as the strength of its adsorption on the surface of the biosensor.The aim of the project is to develop new multilayer nanostructures based on nanolaminates of the plasmonic material/metal oxide type - hyperbolic metamaterials (HMMs). Al-doped ZnO (AZO) and TiN will be used as plasmonic materials, while Al2O3 and ZnO layers will be used as metal oxides. The structural, electrical and optical properties of the new multilayer nanostructures will be investigated. In addition, the relationship between key optical parameters (refractive index, plasma frequency or extinction coefficient), composition and geometry of the fabricated nanostructures will be analysed. Functionalisation of the surface of the nanostructures will be performed and its influence on the optical properties and the mechanism of interaction between cancer biomarkers and the biosensor surface will be investigated.