CARBON INCORPORATION IN (ALGA)AS, (ALIN)AS AND (GAIN)AS TERNARY ALLOYS GROWN BY MOLECULAR-BEAM EPITAXY

Carbon incorporation in III-V ternary alloys, (AlGa)As, (AlIn)As and (GaIn)As, for the entire composition range is investigated using solid-source molecular beam epitaxy. On the binary corners, carbon-doped GaAs and AlAs show p-type conduction, while carbon-doped InAs shows n-type conduction. At a constant doping level, conduction-type inversion is found to occur in the (GaIn)As layer at an InAs mole fraction of about 0.6 and in the (AlIn)As layer at about 0.9. Hall mobilities and free carrier concentrations decrease around the compositions where the conduction-type inversions occur. The conduction-type inversion phenomena and the behavior of carrier mobilities are explained in terms of a self-compensation mechanism.