Effect of Al mole fraction on electron emission at the AlxGa1−xAs/GaAs interface

We report the first direct measurement of electron storage time at the AlxGa1−xAs/GaAs interface as a function of Al mole fraction x. Storage capacitors with x=0.4, 0.6, 0.8, and 1.0 were fabricated and their inversion layer electron retention times measured. The optimal mole fraction for electron retention is in the range 0.4≤x≤0.6.