Identification of residual donors in high-purity undoped p-type epitaxial GaAs by magnetophotoluminescence

Abstract
The residual donor species, Si, S, and Ge, have been identified in high‐purity undoped p‐type epitaxial GaAs grown by metalorganic chemical vapor deposition and arsenic trichloride vapor phase techniques using the magnetic splittings of ‘‘two‐electron’’ replicas of donor bound exciton transitions at low temperature (∼1.8 K) and at a high magnetic field (9.0 T). This technique permits identification of donors in certain high‐purity p‐type GaAs samples in which donor species cannot be identified by photothermal ionization spectroscopy or any other technique.