Enhanced Yb3+-related 0.98 μm emission in porous silicon and its time decay characteristics

A strong enhancement in the intensity of the similar to 0.98 mu m emission (F-2(5/2)-->F-2(7/2),,?) Of Yb3+-ions in I porous silicon is obtained by adding a pre-annealing process to host porous silicon in O-2 or H-2 prior to Yb3+-ion incorporation and subsequent post-dope annealing. The luminescence intensity shows a small temperature quenching, decreasing from 20 K to 300 K by a factor of similar to 10. The time decay measurements show that there are two major Yb3+-related luminescence centers in Yb-doped porous silicon. One is a fast decaying center with a decay time of similar to 30 mu s at 20 K which decreases rapidly with increasing temperature. The other is a slowly decaying center with an almost temperature independent decay time of similar to 400 mu s. The latter is responsible for the small temperature quenching of Yb3+-related 0.98 mu m emission. (C) 1998 American Institute of Physics. [S0021-8979(98)02702-9].