Lateral-Surface-Superlattice Structure on GaAs/AlGaAs for Far-Infrared and Magnetocapacitance Measurements.

摘要

Starting with electrons confined to a two-dimensional electron gas (2DEG), as in Silicon/Silicon Dioxide MOSFETs or Gallium Arsenide/Aluminum Gallium Arsenide modulation-doped layers, the electron motion parallel to the plane of the heterointerface can be further restricted to one or zero dimensions by means of field-effect-induced potential modulation. We have built four-probe Van der Pauw structures on GaAs/AlGaAs modulation-doped layers. On top of the 4 x 4 mm active area we fabricated a 200 nm period Titanium/Gold Schottky metal grid-gate using x-ray nanolithography, evaporation, and liftoff. Electrons traveling from one contact to the other suffer electron back diffraction at specific gate voltages resulting in transconductance oscillations. Magneto-capacitance measurements indicate two sets of quantum oscillations corresponding to the charge density under and in-between the Schottky metal lines. Fair infrared cyclotron resonance measurements show a shift in the resonance peak as a function of gate bias. Reprints. (AW)