Dense Si nanostructures embedded in silicon nitride prepared by plasma-enhanced chemical vapor deposition (PECVD) was used as luminescence active layer to fabricate light-emitting diodes based on p-Si/SiN-based emitter/AZO structure. Visible electroluminescence from the device was observed at room temperature. It is found that the electroluminescence intensity of the device can be further enhanced significantly by inserting an ultrathin nanocrystalline Si layer between the p-Si substrate and SiN-based emitter as a hole barrier layer. Moreover, the electroluminescence efficiency is increased by more than 80% as compared to the decice without the nc-Si barrier layer.