Reappearance of linear hole transport in an ambipolar undoped GaAs/AlGaAs quantum well.

We report the results of an investigation of ambipolar transport in a quantum well of 15 nm width in an undoped GaAs/AlGaAs structure, which was populated either by electrons or holes using positive or negative gate voltage V , respectively. More attention was focussed on the low concentration of electrons n and holes p near the metal-insulator transition (MIT). It is shown that the electron mobility [Formula: see text] increases almost linearly with increase of n and is independent of temperature T in the interval 0.