Group-V antisite defects, VGa, in GaAs.

For more than a decade the interest ingroup-V antisite def ects in GaAs was focusing on the intrinsic AssubGa defect. More recently, when GaAs samples doped with isovalent group-V impurities became available, also group-V heteroantisites on the Ga site were discovered. These include PsubGa, SbsubGa and BisubGa. Such defects are double donors which in their singly ionized state can be observed by conventional electron-spin-resonance (ESR) or, with even better sensitivity, by ESR detected via the magnetic- circular-dichroism (MCD) of the absorption (MCD-ESR). Their chemical identification is based on the characteristic hyperfine structure observed in each case. The resonance spectra and the origin of the MCD absorption bands are discussed. General trends for donor level energies and antisite formation probabilities in the sequence AssubGa, SbsubGa, BisubGa are pointed out.