Dresden 2011 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 85: Poster Session II
HL 85.38: Poster
Donnerstag, 17. März 2011, 18:00–21:00, P4
Concept of a ballistic transfer device in a GaAs/AlGaAs 4-terminal structure using electron refraction — •Michael Szelong1, Daniel Salloch1, Ulrich Kunze1, Dirk Reuter2, and Andreas Wieck2 — 1Lehrstuhl für Werkstoffe und Nanoelektronik, Ruhr-Universität Bochum — 2Lehrstuhl für angewandte Festkörperphysik, Ruhr-Universität Bochum
We present a concept of a ballistic four-terminal device based on electron trajectory refraction, resembling a directional coupler. The device structure consists of a straight stem (1 µm wide and 2 µm long) while two branches merge at each end of the stem under an angle of 45∘ (27∘) with the stem’s longer axis of symmetry.
Devices with different angles and injector widths are processed on a high-mobility GaAs/AlGaAs heterostructure with a two-dimensional electron density and mobility of n2D = 2 · 1011 cm−2 and µ = 2.4 · 106 cm2/Vs, respectively, resulting in a mean free path of 18 µm at T = 4.2 K. A mix-and-match process is used which combines the advantages of nano-scale electron beam lithography with time-saving UV-lithography. The resist pattern is transferred into the heterostructure by wet etching in a citric acid solution. After contact alloying a local Schottky-gate is deposited onto the stem.
Electron trajectories, starting at one branch, will be refracted at the boundary of the gate-controlled region according to Snell’s law of electron refraction [1]. Depending on the direction of refraction electrons will be reflected more or less often at the stem’s boundaries and finally hit one of the opposite branches.
[1] Spector et al., Appl. Phys. Lett. 56, 2433 (1990)