Spectroscopy of donors in high purity GaAs grown by molecular beam epitaxy

Abstract
Photothermal ionization spectroscopy has been used to determine the residual donor species present and their relative concentrations in the highest purity molecular beam epitaxial (MBE) n-GaAs yet reported. Data are presented for samples grown in two different MBE growth reactors: one using elemental As and the other using cracked AsH3 as the arsenic source. In spite of the substantial differences between growth systems, the donor backgrounds are quite similar.