Si δ-doping of 〈011〉-oriented GaAs and AlxGa1−xAs grown by molecular-beam epitaxy

Abstract

Silicon δ‐doping is studied on 〈011〉‐oriented GaAs and Al_xGa_1−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 Al_xGa_1−xAs/GaAs heterostructures, which is explained by the reduced doping efficiency of Si in 〈011〉‐oriented Al_xGa_1−xAs.