Field effect white and tunable electroluminescence from ion beam synthesized Si- and C-rich SiO2 layers

White and tunable electroluminescence has been obtained by field effect injection in 40 nm thick Si- and C-rich SiO2 layers. The films, synthesized by ion implantation, contain Si and C-rich nanoparticles embedded in SiO2 which were formed by annealing at 1100 degrees C. Shifting of the distribution of C-related centers toward the interface region with the substrate allows us to obtain a characteristic white electroluminescence emission under pulsed excitation conditions. Moreover, an evolution of the emission spectrum from white to red is observed by changing the frequency of the pulse. A power efficiency higher than 10(-3)% is estimated. This work opens interesting perspectives on color tunability of field effect electroluminescent devices. (C) 2007 American Institute of Physics.