Structural properties of GaAsN grown on (001) GaAs by metalorganic molecular beam epitaxy

Detailed transmission electron microscopy (TEM) and transmission electron d iffraction (TED) examination has been made of metalorganic molecular beam e pitaxial GaAsN layers grown on (001) GaAs substrates. TEM results show that lateral composition modulation occurs in the GaAs1-xNx layer (x < 6.75%). It is shown that increasing N composition and Se (dopant) concentration lea ds to poor crystallinity. It is also shown that the addition of Se increase s N composition. Atomic force microscopy (AFM) results show that the surfac es of the samples experience a morphological change from faceting to island ing, as the N composition and Se concentration increase. Based on the TEM a nd AFM results, a simple model is given to explain the formation of the lat eral composition modulation.