Chirped GaAs-AlAs distributed Bragg reflectors for high brightness yellow-green light-emitting diodes

A novel chirped distributed Bragg reflector (CDBR) structure was grown by metal-organic chemical vapor deposition (MOCVD) on a GaAs substrate where the optical thickness of each pair decreases monotonically from the bottom of the structure to the top surface. It was found that the fabricated CDBR structure can reflect yellow-green light with a maximum reflectivity of more than 80%, and it can reflect light more efficiently in a wider wavelength range than the conventional DBR structure. Yellow-green AlGaInP LED's with the CDBR structure and the conventional DBR structure were both fabricated. It was found that by using the CDBR structure, one can achieve a higher luminescence intensity.