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HL: Halbleiterphysik

HL 57: Poster IIa

HL 57.12: Poster

Dienstag, 8. März 2005, 16:30–19:00, Poster TU E

Magnetic Freeze-Out in a Double-Barrier Resonant-Tunneling device — •Jens Könemann and R. J. Haug — Inst. f. Festkörperphysik, Uni Hannover, Appelstrasse 2, D-30167 Hannover, Germany

In our work we have investigated the single-electron tunneling (SET)in a double-barrier resonant-tunneling device with a relatively lightly-doped emitter. Our sample is a double-barrier resonant-tunneling device consisting of a 10 nm thick GaAs quantum well with 5 nm and 8 nm thick Al_0.3Ga_0.7As tunneling-barriers and of a highly-doped emitter with a nominal dopant concentration of 1· 10¹⁷ cm⁻³. We observe in our transport data a temperature and magnetic-field dependent shift of the position of the SET current steps which we interprete as a magnetic freeze-out of electrons in the emitter of our device. As a result, we are able to extract typical activation energies of the low-temperature transport below between 350 mK and 1 K.