Growth of AlInN/AlGaN distributed Bragg reflectors for high quality microcavities

We report on the growth of lattice-matched AlInN/AlGaN distributed Bragg reflectors (DBRs) by metal-organic vapor phase epitaxy. Growing these structures on a lattice-matched AlGaN template, the formation of cracks was completely supressed and strain-related structural degradations were avoided. A 35-pair DBR provides a peak reflectivity of 99% at a wavelength of ∼360 nm with a stop band width of 18 nm. Thus, the DBRs are well suited for the application in high Q-factor microcavities designed for the ultraviolet spectral region. However, spatially resolved X-ray diffraction shows an increase of the DBR period thickness towards the edge of the wafer, leading to a strong red-shift of the stop band of ∼35 nm. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)