Magnetic circular dichroism and optical detection of electron paramagnetic resonance of the SbGa heteroantisite defect in GaAs:Sb

In an investigation of GaAs doped with Sb to a concentration of approximately equal to 1 x 10high19 cmhighminus3, the electron-paramagnetic-resonance (EPR) signal of the SbsubGa heteroantisite defect has been optically detected by monitoring the microwave-induced changes in the magnetic-circular-dichroism (MCD) absorption signal. All hyperfine transitions expected for the two Sb isotopes (high121Sb and high123Sb) were observed and the identification of the SbsubGa defect is thus confirmed. The g value is 2.02 and the hyperfine constants are 0.220 cmhighminus1 (for high121Sb) and 0.120 cmhighminus1 (for high123Sb). The MCD signal of the SbsubGa defect has been measured being tagged to the EPR signal, and a comparison with the corresponding spectrum for the AssubGa (EL2) defect is made. The existing models fail to give a satisfactory explanation for the MCD spectra.