We have investigated the effects of a transparent SiCN doping layer on electrical and optical performance of silicon nanocrystal (nc-Si) light-emitting diodes (LEDs). The optical bandgap of SiCN doping layer shifted to a shorter wavelength with increasing N composition into the SiCN doping layer, which was estimated from 2.2 to 2.6 eV by applying the Tauc model. The electrical property of the nc-Si LED by employing a transparent SiCN doping layer was enhanced compared to that of the nc-Si LED with a SiC doping layer. This could be attributed to a reduction in the tunnel barrier of electrons into the nc-Si from the doping layer due to the higher bandgap of the SiCN doping layer than the SiC doping layer. In addition, the power conversion efficiency (output power/input power) was also improved by 41%. The results suggested that a transparent SiCN doping layer was a very effective way to improve the performance of nc-Si LEDs. Moreover, we demonstrated the 8x8 mu-LED array with stable and uniform light emission. (C) 2008 The Electrochemical Society.