| An experimental study of the nonlinear properties of a ballistic three-branch junction is presented. Ballistic electron transport in these devices is responsible for a nonlinear input-output transfer curve that has been exploited in the literature for applications such as signal rectification, frequency multiplication and designing logic gates. The devices studied here were fabricated using a self-aligning mask technique that is expected to provide improvements over conventional electron-beam resist masks. Electrical measurements were carried out in a two-input passive mode where finite voltages Vl and V r are applied in a push-pull manner (Vl =V and Vr=-V) to the left and right terminals, respectively, of the junction. The output of the central probe voltage VC was found to be rectifying at all values of the applied voltage, consistent with earlier work. VC evolved from a parabolic dependence, Vc ∝ -Vl,r 2, indicative of ballistic rectification, to a linear one at higher biases, indicative of strong energy relaxation. Temperature dependent studies of the dependence of VC on bias were also performed. At 77 K, the time-dependent variation of VC under zero applied bias revealed some evidence of charge leakage from a Coulomb island, formed unintentionally in the center of the three-branch junction. This behavior may suggest new avenues for the development of nanoelectronic logic and memory devices. |
