Photoluminescence characterization of molecular beam epitaxial GaAs grown using cracked AsH₃

High purity undoped molecular beam epitaxial GaAs layers grown using cracked AsH₃ as the As source have been characterized by low-temperature (1.7-20 K) photoluminescence measurements. The dominant residual acceptor was found to be either Mg or Be (which cannot be distinguished by this technique), with smaller amounts of C, Si, Ge, Sn, and Mn also present. The incorporation of residual amphoteric impurities depends strongly on the As to Ga flux ratio. The]] defect"-related luminescence characteristic of material grown with a solid As source was not detected. A sample grown in the same system using solid As showed only C acceptors but did produce defect luminescence.