Abstract: Converter device for converting energy from electromagnetic radiation, in particular concentrated solar energy, in electrical power, comprising a thermionic emitter (2) and an absorber (1) of electromagnetic radiation, configured to transform electromagnetic radiation energy to thermal energy, having an outer surface (10) configured to be exposed to electromagnetic radiation and an inner surface integrally coupled to the thermionic emitter (2), the outer surface (10) being provided with a sub-micrometer periodic surface structure, the thermionic emitter (2) being monolithically integrated on said inner surface of the absorber (1), the absorber (1) being made of a material selected from the group comprising or consisting of carbide or aluminium nitride-based ceramic materials, and pyrolitic graphite, the thermionic emitter (2) being made of a material selected from the group comprising or consisting of thin film diamond deposited through chemical vapour deposition (CVD), thin film titanium nitride (TiN) or mol

Abstract: Method for fabricating a structure comprising a monatomic layer of crystalline silicon upon an electrically insulating layer of crystalline silicon nitride in the ? structural form, comprising the following steps: A. providing a standalone Si (111) substrate, said substrate comprising a first face and a second main face; B. thermally treating the substrate so that the Si (111) surface is clean, i.e. non contaminated at an atomic level; C. thermally growing a crystalline silicon nitride layer in the 13 structural form on at least one face of said Si (111) substrate; D. thermally growing a crystalline silicon monatomic layer on the crystalline silicon nitride layer.