SI DELTA-DOPING OF (011)-ORIENTED GAAS AND ALXGA1-XAS GROWN BY MOLECULAR-BEAM EPITAXY

Silicon delta-doping is studied on [011]-oriented GaAs and AlxGa1-xAs grown by molecular-beam epitaxy. Hall measurements and secondary ion mass spectrometry on as-grown and on annealed samples reveal (i) that the electrical activity is reduced for the [011]-oriented samples as compared [001]-oriented reference samples, (ii) that the electron mobility is lower for [011]-oriented samples, and (iii) that the thermal redistribution of Si impurities is comparable for both orientations. We find a markedly different dependence of the electron mobility on the spacer thickness in selectively doped [011]-oriented AlxGa1-xAs/GaAs heterostructures, which is explained by the reduced doping efficiency of Si in [011]-oriented AlxGa1-xAs.