Nitrogen incorporation in GaAsN grown by chemical beam epitaxy

Chemical beam epitaxial growth system has been developed for achieving good quality InGaAsN thin film, which will be adopted as a third material of four-junction tandem solar cell. Methylhydrazine, which was used as a N source, was decomposed on the growing surface. Between 400-420°C, N concentration had slight temperature dependence. The adsorbed N-related molecules hindered the decomposition of Ga precursor TEG on the surface, resulting in the decrease of the growth. Above 440°C, the number of N incorporated in the grown film swiftly decreased. The growth rate had slight temperature dependence and the quality of grown film became deteriorated although the amount of residual N decreased.