Photothermal ionization identification of sulfur donors in GaAs

Abstract
Photothermal ionization data for undoped and S-doped epitaxial GaAs grown by metalorganic chemical vapor deposition (MOCVD) are presented which permit the positive identification of the S donor. This identification is unambiguous because S is not a significant residual impurity in the undoped MOCVD GaAs used for these measurements. Implications of the new identification for the importance of S as a residual donor in epitaxial GaAs prepared by various other growth techniques.