Excitation cross section of erbium in semiconductor matrices under opticalpumping - art. no. 075302

Based on a detailed consideration of excitation mechanisms of erbium in cry stalline and amorphous matrix we present an analysis of the physical meanin g of the Auger excitation cross section of Er3+ ions in semi-conductor. It is demonstrated that large values of Auger excitation cross sections under optical pumping in semiconductor matrices are due to large values of band-t o-band absorption coefficient exceeding by several orders of magnitude the absorption coefficient of erbium in dielectric SiO2 and Al2O3 matrix. The A uger excitation cross section of Er3+ in semiconductor matrices is roughly given by the ratio of the matrix absorption coefficient to concentration of Er3+ ions. While the analysis of the excitation cross section is carried o ut for Er-doped crystalline and amorphous silicon, the results are expected to be applicable to the other rare-earth doped semiconductors. Based on lo w-temperature experimental results for crystalline silicon we get the Auger excitation coefficient of c(A)(cryst)approximate to7 x 10(-10) cm(3) s(-1) and the effective excitation cross section sigma (cryst)(eff) = (2 - 8) x 10(-12) cm(2). For amorphous silicon at 100 K we obtain sigma (amorph)(eff) approximate to 1.4 x 10(-14) cm(2).