Optical properties of surface grated Si-based multilayer structure

Boron doped Si/SiO2/substrate (Si:B) structure with subwavelength grating on the top Si:B layer was studied by spectroscopic ellipsometry and photoluminescence spectroscopy at room temperature. A clear modification of the dielectric function was observed after reactive ion etching of the top Si:B layer subjected to laser lithography to make a subwavelength grating with high precision. A striking feature of the dielectric function of the grated surface layer is a sharp and intense peak at the energy of 2.968 eV in the interband density of states. Emission band with a remarkable peak structure that emerges in the photoluminescence spectrum of the grated multilayer structure at and below the last energy is absent on pure or boron doped Si. The obtained results are discussed in terms of the G-doping effect in the considered surface grated multilayer structure.