Specific features of the nonradiative relaxation of [Er.sup.3+] ions in epitaxial Si structures

The specific features of the nonradiative relaxation of [Er.sup.3+] 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 [Er.sup.3+] 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.sub.0] ≅ 5 x [10.sup.16] [cm.sup.-3]). In terms of order of magnitude, the estimated concentration [N.sub.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 [Er.sup.3+] ions in Si: Er/Si structures with different types of emitting centers are analyzed. DOI: 10.1134/S1063782614120112