Nitrogen related vacancies in GaAs based quantum well superlattices

The authors report on the influence of nitrogen incorporation on vacancies in GaAs based superlattices. The samples were molecular beam epitaxy grown on p -type GaAs substrates with the superlattice structure consisting of ten periods of quantum well material separated by GaAs buffers. Three different quantum well compositions were used, Ga 0.63 In 0.37 As , Ga 0.63 In 0.37 N 0.01 As 0.99 , and Ga N 0.01 As 0.99 . Rapid thermal anneals were performed on each sample set. Positron spectroscopy was used for vacancy detection in the superlattice structure. Annealed GaNAs and GaInNAs superlattice samples were found to contain vacancy-type defects. A comparison with photoluminescence measurements shows that the detected vacancy-type defects are not optically active.