HIGH-FREQUENCY CONDUCTIVITY OF ION-BEAM-DEFINED QUANTUM WIRES WITH A SELF-ALIGNED GATE

Quasi one-dimensional quantum wire arrays are fabricated by low-energy ion beam exposure of AlGaAs-GaAs heterostructures containing a high-m obility two-dimensional electron system (2DES). The mask used for the ion beam exposure consists of a metal grating evaporated on the crysta l surface, which also serves as a gate after irradiation. This self-al igned gate allows us to change the electron density in the wires witho ut changing the electronic wire width. The linewidths of the dimension al resonances in the far infrared (FIR) of these wire arrays confirm t his assertion. The FIR transmission spectra are compared with previous results obtained using wire arrays that were density tuned with a dis tance-modulated gate. Furthermore, a higher-order resonance is observa ble, indicating that the confinement potential has non-parabolic contr ibutions.