Evidence for ballistic electron transport exceeding 160 μm in an undoped GaAs/AlxGa1-xAs field-effect transistor
Abstract
We report measurements of GaAs/AlxGa1-xAs undoped field-effect transistors in which two-dimensional electron gases (2DEG's) of exceptional quality and versatility are induced without modulation doping. Electron mobilities at T=4.2 K and density 3×1011 cm-2 exceed 4×106 cm2 V-1 s-1. At lower temperatures, there is an unusually large drop in scattering, such that the mobility becomes too high to measure in 100-μm samples. Below T=2.5 K, clear signatures of ballistic travel over path lengths in excess of 160 μm are observed in magnetic-focusing experiments. Multiple reflections at the edges of the 2DEG indicate a high degree of specularity.
- Publication:
-
Physical Review B
- Pub Date:
- February 1999
- DOI:
- 10.1103/PhysRevB.59.4622
- Bibcode:
- 1999PhRvB..59.4622F
- Keywords:
-
- 73.23.Ad;
- 72.15.Lh;
- 73.50.Gr;
- Ballistic transport;
- Relaxation times and mean free paths;
- Charge carriers: generation recombination lifetime trapping mean free paths