Indium tin oxide/Si-rich SiO2/p-Si structured devices are fabricated to study the electroluminescence (EL) of the Si-rich SiO2 (SRO) material. The obvious peaks at ～1050nm and ～1260nm in the EL are ascribed to localized state transitions of amorphous Si (α-Si) clusters. The EL afterglow associated with α-Si clusters is observed from this structure at room temperature, while the afterglow is absent in the case of optical pumping. It is believed that carrier-induced defects act as trap centres in the α-Si clusters, resulting in the EL afterglow. The phenomenon of the EL afterglow indicates the limits of EL performance and electrical modulation of the SRO material with a larger fraction of α-Si clusters.