We have focused on improving luminescent intensity and reducing direct current (DC) voltage of a nanocrystalline silicon (nc-Si) particle based electroluminescent (EL) device. Nc-Si particles with a size of 3.0 nm dispersed in ethanol were utilized as the luminous layer of the EL device. The EL device could be efficiently injected with carriers (electrons and holes) in the nc-Si region at a low DC voltage of 2.5 V The injection of carriers resulted in red luminescence that was clearly visible to the naked eye. This was achieved at a low DC voltage by tuning the thickness of the oxide layer surrounding nc-Si particles. (C) 2007 Elsevier B.V. All rights reserved.