Intracenter transitions in triply ionized erbium ions diffused into III-V compound semiconductors
Xinwei Zhao, Kazuhiko Hirakawa, Toshiaki Ikoma
The rare-earth element, erbium (Er), was successfully diffused into GaAs and InP for the first time. Two intense and three weak sharp photoluminescence (PL) lines related with Er were observed at a wavelength of ∼1.55 μm both in GaAs and InP. It was found, for the first time, that the emission energy and the linewidth of the two intense Er-related PL lines do not depend on temperatures up to 220 K. This clearly indicates that these sharp emission lines are due to 4f-intracenter transitions in triply ionized erbium (Er3+) ions, and that the 4f orbitals are well shielded from a crystal field by the outer closed orbitals. Furthermore, it was found that the intensity ratio of the five emission lines from Er3+ is independent of the excitation power density. The results reveal that the Er3+ ion substitutes a cation site both in GaAs and InP, and that the five PL lines correspond to the transitions from the first excited state to the five crystal-field-split ground states of Er3+ ion with a tetrahedral (Td) symmetry.
Applied Physics Letters•Feb 20, 1989•27 citations