Fabrication and characterization of ambipolar devices on an undoped AlGaAs/GaAs heterostructure

We have fabricated AlGaAs/GaAs heterostructure devices in which the conduction channel can be populated with either electrons or holes simply by changing the polarity of a gate bias. The heterostructures are entirely undoped, and carriers are, instead, induced electrostatically. We use these devices to perform a direct comparison of the scattering mechanisms of two-dimensional electrons (mu(peak) - 4 x 10(6) cm(2)/Vs) and holes (mu(peak) - 0.8 x 10(6) cm(2)/Vs) in the same conduction channel with nominally identical disorder potentials. We find significant discrepancies between electron and hole scattering, with the hole mobility being considerably lower than expected from simple theory. (C) 2012 American Institute of Physics. [doi: 10.1063/1.3673837]