Enhanced mobility in inverted AlxGa1−xAs/GaAs heterojunctions: binary on top of ternary

Abstract

Single-period modulation doped inverted Al0.18Ga0.82As/GaAs heterostructures having the binary on top of the ternary were grown by molecular beam epitaxy. Despite the early reports of no mobility enhancement, considerable mobility enhancement, particularly at cryogenic temperatures, were obtained in the present structures. Mobilities of about 27 600 cm2/Vs with associated sheet carrier concentrations of about 6×1011 cm−2 were obtained at 10 K. The results represent the first enhanced mobilities obtained by molecular beam epitaxy and compare with 25 600 cm2/Vs deduced from Shubnikov de Haas measurements in LPE-grown structures at 4 K.