Bragg scattering from periodically microstructured light emitting diodes

We present a simple method of generating a periodic wavelength scale struct ure in the optically active layer of a light emitting diode. This is achiev ed by solution deposition of a light emitting polymer on top of a corrugate d substrate. The periodic structure allows waveguide modes normally trapped both in the substrate and in the thin polymer film to be Bragg scattered o ut of the structure, thus leading to a doubling of efficiency. This scatter ing process gives rise to a polarization of the emission spectrum as well a s angular dispersion effects. (C) 2000 American Institute of Physics. [S000 3-6951(00)03043-6].