A light emitting device is disclosed comprising a bottom layer of electrically conductive material. A block of electrically insulating material is disposed on the bottom layer. At least a portion of the block is optically transparent. A top layer of electrically conductive material is disposed on the block. A plurality of discrete nano-crystals of a material selected from the group consisting of Group IV, Group III-V, and Group II-VI is disposed within the block, and are thereby electrically insulated from the top and bottom layers. Also provided are bottom and top electrodes connected to the bottom and top layers, respectively, for applying a voltage therebetween.