Ballistic electron transport exceeding 160 µm in an undoped GaAs/AlGaAs FET

Bell Laboratories, Lucent Technologies, Murray Hill NJ 07974 USA(May 19, 2011)We report measurements of GaAs/AlGaAs undoped field-effect transistors in which two-dimensional electron gases(2DEGs) of exceptional quality and versatility are inducedwithout modulation doping. Electron mobilities at T = 4.2 Kand density 3 × 10