Electron mobilities in modulation doped Ga0.47In 0.53As/Al0.48In0.52 As heterojunctions grown by molecular beam epitaxy

Abstract

Modulation doped Ga0.47In0.53As-Al 0.48In0.52 As single-period heterostructures have been prepared by molecular beam epitaxy (MBE). Electron mobilities as high as 8915 cm2/V s at 300 K, 60 120 cm2/V s at 77 K, and 90 420 cm2/V s at 10 K were obtained with an average electron concentration of ∼1017 cm-3. These results represent a mobility enhancement over uniformly doped Ga0.47In0.53 As with the same carrier concentration by about a factor of 6 at 77 K and by a factor of 2 at 300 K. Single-period modulation doped heterostructures have shown enhanced mobility in spite of the relative positions of the Si-doped Al 0.48In0.52 As layer and the undoped Ga 0.47In0.53 As layer in contrast to the case of GaAs/AlxGa1-x As system where mobility enhancement has only been observed for MBE grown AlxGa1-x As on top of the undoped GaAs layer.