Formation and optical properties of locally strained Ge microstructures embedded into cavities

The formation of locally strained Ge microstructures (microbridges) on silicon-on-insulator (SOI) substrates embedded into cavities and the results of studies of the optical properties of such structures are reported. A cavity design compatible with the geometry of the locally strained active region is calculated so that it provides, on the one hand, efficient localization of the electromagnetic field in the active region of the structure and, on the other hand, minimizes the influence of the cavity on the magnitude and distribution of strains in the structure. The experimentally obtained microphotoluminescence spectra demonstrate a considerable increase of the signal intensity from the strained regions of Ge microstructures compared to the initial Ge film. It is shown that the formation of cavities yields a reduction of strains in Ge microbridges, but provides an increase of the photoluminescence intensity of the structures.