Shifted X-Ray Photoelectron Peak in Molecular-Beam Epitaxial GaAs Grown at 200 Degrees C

X‐ray photoelectron spectroscopic results show that molecular beam epitaxial GaAs grown at 200 °C has a reduced effective surface potential energy, about 0.5 eV, compared with the usual 0.7 eV. A Poisson analysis of the data, using parameters from Hall effect and absorption measurements, requires that the Fermi‐level‐controlling defect in this material must have a significantly lower activation energy than that of EL2, an unexpected result