An isolated acceptor impurity is shown to be responsible for the sim;113hyphen;meV deep luminescence band which is frequently seen in GaAs layers grown by molecularhyphen;beam epitaxy. We establish that this center, which is also observed in melthyphen;grown and solutionhyphen;grown GaAs and which has often been associated with the presence of native defects, is due to Mn. The luminescence arises from donorhyphen;acceptor and conductionhyphen;bandndash;acceptor recombination involving holes bound at the Mn acceptor. Electron paramagnetic resonance on Mnhyphen;doped layers shows that Mn is incorporated as an isolated defect with cubic symmetry. This result, coupled with the suppression of Mnhyphen;associated luminescence and electrical activation under Gahyphen;rich growth conditions, indicates that Mn is incorporated primarily as a substitutional acceptor on Ga sites. Hole concentrations scale with Mn source temperature in a manner consistent with arrivalhyphen;ratehyphen;controlled incorporation from a Knudsen effusion source. Roomhyphen;temperature hole concentrations up to the 1018hyphen;cmminus;3level can be achieved while maintaining excellent surface morphology. This suggests that Mn will be a useful dopant in the growth of junction structures by molecularhyphen;beam epitaxy.
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