In this contribution we give an overview of our development of size-controlled multilayered ensembles of silicon nanocrystals (Si-NCs) for efficient light emitting devices (LEDs). The ensembles of Si-NCs embedded in silicon dioxide are grown by chemical vapour deposition methods and by using standard microelectronic processes. The formation of nanocrystals is monitored by several analytical techniques. Novel LED architectures of nanocrystal ensembles which improve electrical injection and light emission are described. Charge tunnelling in nanosilicon superlattices, light emission efficiency under direct and alternating current injection, and device stability are discussed. Visible light emission from an electroluminescence (EL) device with Si-NCs.