Effective excitation cross section of erbium in amorphous hydrogenated silicon under optical pumping

The effective excitation cross section of erbium embedded in an amorphous s ilicon matrix and the total lifetime of erbium ions in the excited state ar e determined by measuring the photoluminescence rise time of erbium ions un der pulsed excitation of erbium-doped amorphous hydrogenated silicon. An an alysis of the rate equations describing the excitation and deexcitation of erbium ions in a semiconducting matrix sheds light on the physical meaning of the effective excitation cross section. It is shown that measurement of the effective excitation cross section permits evaluation of the concentrat ion of optically active erbium ions in the amorphous silicon matrix. (C) 20 01 MAIK "Nauka/Interperiodica".