Photonic band structure and emissive characteristics of MEH-PPV textured microcavities

A detailed comparison is made between the experimentally determined photoni c band structure and the measured angle-dependent emission spectra of textu red, metal-clad microcavities containing the light-emitting polymer MEH-PPV . Transmittivity measurements were made over a range of optical frequency a nd in-plane wavevector in order to obtain a detailed map of the dispersion of the waveguide modes supported by the textured cavities. Emission spectra were also recorded, for a large number of sample orientations, and are com pared with the transmittivity maps. It is found that the band structure str ongly influences the wavelength of the peaks in the emission spectra, and t hat the periodic texture leads to the generation of Bragg-scattered emissio n. The positions of these spectral peaks in both frequency and in-plane wav evector are found to agree very well with the positions of peak transmittiv ity of the cavities. The emission spectra also show clear evidence of the p hotonic band gaps formed by the periodic texture. The importance of these f indings for light-emissive devices such as the light emitting diode is disc ussed.