GA FOCUSED-ION-BEAM SHALLOW-IMPLANTED QUANTUM WIRES

Quantum wires were fabricated by shallow implantation of Ga ions from a focused-ion-beam source into a modulation-doped AlxGa1-xAs/GaAs hete rostructure. This type of implantation reduces crystal damage and keep s the implanted ions away from the two-dimensional electron gas. An el ectron mobility as high as 5.04 X 10(5) cm(2)/V s was obtained for 10- mu m-long wires with an effective width of 0.152 mu m, which is much h igher than any previously reported values. The electron ballistic leng ths in the wires were determined from measurements of the bend and tra nsfer resistance and agreed well with the calculated elastic mean free paths. The transfer resistance versus magnetic field profiles exhibit ed electron focusing peaks associated with good specularity at the bou ndary. (C) 1997 American Vacuum Society. [S0734-211X(97)00305-3].