Transport properties of GaAs-AlxGa1−x As heterojunction field-effect transistors

We report low field transport properties of n-channel GaAs-AlxGa1−x As heterojunction field-effect transistors. Studies of the Shubnikov-de Haas effect confirm that the devices are insulated-gate field-effect transistors, with AlxGa1−x As as the gate insulator. The channel mobility increases with density following μ2∼ nγ, with γ varying from 0.45 to 1.4. μ = 1.2×105 cm2/V sec at 78 K and 3.6×105 cm2/V sec at 4.2 K are observed at n∼4×1011/cm2.