Optically detected magnetic resonance of group-IV and group-VI impurities in AlAs and ${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As with x≥0.35

Optically detected magnetic-resonance (ODMR) experiments have been performed on n-doped epitaxial layers of AlAs and ${\mathrm{Al}}_{\mathit{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As with x≥0.35 grown on (001) GaAs substrates. The ${\mathrm{Al}}_{\mathit{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As layers were doped during growth or via implantation with Si and Sn impurities from group IV and S, Se, and Te impurities from group VI. The studies were carried out with the as-grown layers on the parent GaAs substrates, removed from the substrates, and attached to substrates with larger lattice constants at low temperatures. Symmetry information was obtained from angular-rotation studies with the magnetic field rotated in the (11¯0) and (001) crystal planes. Also, uniaxial stress along the [11¯0] and [100] directions has been combined with ODMR to further probe the symmetry of the donor states.