Design of a resonant-cavity-enhanced p-i-n GaN/AlxGa1-xN photodetector

A resonant-cavity-enhanced p-i-n photodetector has been designed and analyz ed to operate at a wavelength of 360 nm based on the AlxGa1-xN material sys tem. The novel approach has been adopted of using epitaxial AlN/AlxGa1-xN q uarter-wave stacks as the distributed Bragg reflector that serves as the fr ont mirror. An AlxGa1-xN absorptive filter layer is incorporated in suppres s all but one resonant mode to ensure single, narrow-band operation. This d evice structure is projected to achieve wavelength selective, high speed, a nd high quantum efficiency operation in the ultraviolet. MOCVD-grown 6 1/2- pair AlN/AlxGa1-xN Bragg reflectors with peak reflectivities of similar to 57% have been demonstrated The spectral reflectivity data are found to be i n agreement with results of S-matrix simulations with scattering due to int erface roughness taken into account.