Doping density dependence of 4f-4f couplings between Er and Yb ions in nanocrystalline Si

Abstract

This paper presents the formation and time-resolved investigation of Er and Yb co-doped nc-Si thin films. Since the energy of the only one excited state /sup 2/F/sub 5/2/ of a Yb/sup 3+/ ion is almost same to that of the second excited state /sup 4/I/sub 11/2/ of an Er/sup 3-/ ion, the optical transition between them is expected to raise the excitation rate of the Er/sup 3+/ ion.