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

Facer, G. R.; Kane, B. E.; Dzurak, A. S.; Heron, R. J.; Lumpkin, N. E.; Clark, R. G.; Pfeiffer, L. N.; West, K. W.

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

Authors

Description

We report measurements of GaAs/AlGaAs undoped field-effect transistors in which two-dimensional electron gases (2DEGs) of exceptional quality and versatility are induced without modulation doping. Electron mobilities at T=4.2 K and density 3 E11 /cm^2 exceed 4 E6 cm^2/Vs. At lower temperatures, there is an unusually large drop in scattering, such that the mobility becomes too high to measure in 100 micron samples. Below T=2.5 K, clear signatures of ballistic travel over path lengths in excess of 160 microns are observed in magnetic focusing experiments. Multiple reflections at the edges of the 2DEG indicate a high degree of specularity.
RevTeX file: 5 pages with 6 included PS/EPS files (21/5/98) Typographical error corrected 26/6/98