PULSED FAR-INFRARED SPECTROSCOPY OF GAAS-CR AT HIGH MAGNETIC-FIELDS IN THE FIELD-MODULATION MODE

A magnetic field-modulation technique has been developed for sensitive far infrared electron paramagnetic resonance (EPR) spectroscopy on Cr2+ centers in GaAs. A hundred-fold improvement in signal-to-noise ratio relative to non-modulation techniques was obtained. The results of this experiment have been analyzed and agree well with a spin Hamiltonian and parameters obtained from microwave EPR studies of Cr2+ in GaAs. No evidence could be found to support the view that this ground state is the terminal level of the finely structured 0.839 eV luminescence line reported in earlier high resolution absorption and luminescence studies. © 1979.