Properties of erbium silicate doped with chromium in porous silicon

The possible formation of chromium-doped erbium silicate Er₂SiO₅: Cr in thin layers of porous silicon is demonstrated. This paper reports on studies of the photoluminescence, electron paramagnetic resonance, and transverse current transport in porous silicon layers (with different chromium and erbium contents) grown on n-and p-silicon single crystals heavily doped with shallow impurities. The Er₂SiO₅: Cr phase with the photoluminescence maxima at approximately 1.3 and 1.5 μm manifests itself after high-temperature annealing at 1000°C. The introduction of erbium and annealing at 700°C increase the intensity of the red photoluminescence of porous silicon by several factors. The decrease in the electrical conductivity of porous silicon suggests the onset of the formation of erbium silicate. The current-voltage characteristics exhibit a nonlinear behavior with an exponential dependence of the current on the voltage due to the discrete electron tunneling. An electron paramagnetic resonance spectrum of P _b centers in p-type heavily doped silicon is observed for the first time.