Light-emitting device structure (Si/SiO2/low-dimensional Si/Si3N4/Si) is proposed. The low-dimensional Si governed the photon generation efficiency and energy spectrum whereas the asymmetry barrier heights on both sides formed by the SiO2 and Si3N4, respectively, provide high-efficiency carrier injection based on direct tunneling and maximize the rate of the recombination events taking place in the low-dimensional silicon. Detailed theoretical modeling of carrier transportation in this device structure is developed. Theoretical calculations demonstrate that the recombination rate of carrier with this structure can be as high as 3 X 10(23) cm(-2) s(-1) and are governed by the barrier heights, thickness of the dielectric films, and the width of low-dimensional Si region. (c) 2005 American Vacuum Society.