Tellurium-doped Al0.43Ga0.57As/(In0.2)GaAs modulation doped heterostructures by molecular-beam-epitaxy

Abstract

Te has previously been demonstrated to have a shallower deep donor (DX‐center) level than Si in AlGaAs. In this work, Te‐doped Al0.43Ga0.57As/GaAs and pseudomorphic Al0.43Ga0.57As/ In0.2Ga0.8As modulation‐doped heterostructures (MDHs) grown by MBE have been studied. The conduction band offset ΔE c in the pseudomorphic AlGaAs/InGaAs material system has a maximum at 43% Al mole fraction. This allows maximum carrier confinement in the quantum well. Two‐dimensional electron densities and mobilities 2.36×1012 cm−2 and 7794 cm2/V s at 300 K and 2.17×1012 cm−2 and 24 379 cm2/V s at 77 K (in the dark) have been obtained in Te‐doped pseudomorphic MDHs.