Specific features of the nonradiative relaxation of Er3+ ions in epitaxial Si structures

The specific features of the nonradiative relaxation of Er3+ ions in Si:Er layers grown by sublimation molecular-beam epitaxy (SMBE) are studied. In Si:Er/Si diode structures containing precipitation-type emitting centers, a resonance photoresponse at the wavelength λ ≈ 1.5 μm is observed, which is indicative of the nonradiative relaxation of Er3+ ions via the energy back-transfer mechanism. Saturation of the erbium-related photocurrent is for the first time observed at high temperatures. This allows estimation of the concentration of Er centers that undergo relaxation via the above-mentioned back-transfer mechanism (N 0 ≈ 5 × 1016 cm−3). In terms of order of magnitude, the estimated concentration N 0 corresponds to the concentration of optically active Er ions upon excitation of the Si:Er layers by means of the recombination mechanism. The features of the nonradiative relaxation of Er3+ ions in Si:Er/Si structures with different types of emitting centers are analyzed.