Correlation of two diamagnetic bands of the magnetic circular dichroism of the optical absorption with EL20 in GaAs

In a previous investigation, a diamagnetic band of the magnetic circular dichroism of the optical absorption (MCDA) in semi-insulating GaAs centered at 1.19 eV was observed and attributed to the neutral diamagnetic charge state of EL2, EL20. In this letter, we show a direct correlation between the signal intensities of two diamagnetic MCDA bands located at 0.93 and 1.19 eV and the concentration of neutral diamagnetic EL20 centers in different GaAs samples. A calibration factor is presented for the absolute MCDA intensities. This opens up the possibility of measuring the concentrations of EL20 and EL2+ using the same technique.