The 1.54 mu m Er3+ photoluminescence excitation (PLE) and photoluminescence (PL) spectra of erbium-doped silicon-rich silicon oxide (SRSO) are investigated. Between 350 and 820 nm, PLE spectra are broad and featureless, and the PL spectra are independent of the excitation wavelengths. The results indicate that in erbium-doped SRSO, the Er3+ luminescence is dominated by a single class of Er sites with a strong coupling to all the carriers in the silicon nanograins. (C) 2000 American Institute of Physics. [S0003-6951(00)03313-1].