Multilayer photosensitive structures based on porous silicon and rare-earth-element compounds: Study of spectral characteristics

The spectral characteristics of the specular reflectance, photosensitivity, and photoluminescence (PL) of multilayer structures based on porous silicon with rare-earth-element (REE) ions are investigated. It is shown that the photosensitivity of these structures in the wavelength range of 0.4–1.0 $\mu$m is higher than in structures free of REEs. The structures with Er$^{3+}$ ions exhibit a luminescence response at room temperature in the spectral range from 1.1 to 1.7 $\mu$m. The PL spectrum of the erbium impurity is characterized by a fine line structure, which is determined by the splitting of the $^{4}I_{15/2}$ multiplet of the Er$^{3+}$ ion. It is shown that the structures with a porous layer on the working surface have a much lower reflectance in the entire spectral range under study (0.2–1.0 $\mu$m).