Fine structure in the Er-related emission spectrum from Er–Si–O matrices at room temperature under carrier mediated excitation

Er–Si–O crystalline matrices (ESO) have been synthesized by coating the Si surface with an ErCl/ethanol solution, followed by a two-step annealing process, first in oxygen and second in argon. Fine structures of the Er3+-related photoluminescence (PL) spectrum (line width less than 4 meV) have been observed at room temperature. The PL fine structures indicate Stark splitting of the 4f-electron energy levels in erbium ions. The PL excitation spectrum at room temperature shows the carrier-mediated excitation of Er ions. These results suggest that ESO are of a stable and homogeneous structure in semiconducting silicon matrix and are optically very active. The local environment of erbium ions is discussed from the Stark splitting.