A light emitting diode (100 or 150) includes a diode structure containing a quantum well (120), an enhancement layer (142), and a barrier layer (144 or 148) between the enhancement layer (142) and the quantum well (120). The enhancement layer (142) supports plasmon oscillations at a frequency that couples to photons produced by combination of electrons and holes in the quantum well (120). The barrier layer serves to block diffusion between the enhancement layer (142) and the diode structure.