Ion implantation is used to modify the local environment of theDXcenter in Sihyphen;doped Al0.27Ga0.73As grown by molecular beam epitaxy (MBE), and the variations inDXcenter properties with subsequent rapid thermal annealing processes are examined using deep level transient spectroscopy. In the ashyphen;grown sample, twoDXcenter peaks are found with the same activation energy of 0.46plusmn;0.01 eV, but with widely different cross sections. The mainDXcenter peak ME3, which appears at higher temperatures due to its smaller cross section, remains stable throughout the experiments. The secondDXcenter peak ME2 has a much larger cross section, and appears at a lower temperature. The capture properties of this subsidiaryDXcenter peak are markedly altered in the ionhyphen;implanted samples. Samples which were subject solely to the rapid thermal annealing processes have stableDXcenter trap signatures, indicating that arsenic loss during annealing does not significantly influence theDXcenter characteristics. It is proposed that regions of incomplete ordering and defect complexing in the AlGaAs film give rise to the various subsidiaryDXcenter peaks observed.
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