Unintentional indium incorporation in GaAs grown by molecular beam epitaxy

We have quantified unintentional indium incorporation in GaAs grown by molecular beam epitaxy in a variety of commercial systems. We find that the unintentional indium density in the epitaxial GaAs is more a function of mounting technique and prior machine history than of the manufacturer's design. The indium densities detected in the epitaxial GaAs for substrates that only partially obscure an indium-bearing mount are equal to levels reported to result in minimum defect densities and narrowest photoluminescence linewidths in In-doped GaAs