A simple theoretical model for the magnetic circular dichroism absorption of undoped as-grown GaAs

A simple theoretical model for the magnetic circular dichroism absorption (MCDA) of as-grown semiinsulating GaAs is proposed. It is shown that the MCDA spectrum can be explained in terms of the photoneutralization transition, As+ sub Ga + h ny....As(o) sub Ga + hole, at an As sub Ga antisite defect. There is no need to invoke an As sub Ga complex to fit the MCDA shape. The calculation also accounts satisfactorily for the low temperature shape of the (As sub Ga/El2)+ hole ionization cross section. (IAF)