Ballistic transport and gate control mechanism in deeply etched electron-waveguide based devices

We prepared In 0.53 Ga 0.47 As/InP electron waveguides with in-plane side gates by deep etching through a two-dimensional electron gas. In these structures we investigated the conductance dependent on the voltages applied at both gates. Our experiments show a remarkable asymmetry in the gate efficiency: negative gate voltages seem to be more efficient than positive ones, and the pinch-off voltage of the waveguide depends mainly on the more negative of the two gate voltages. A model is given which takes the etched surfaces into account. The conductance in the waveguide is essentially determined by the potentials at the etched surfaces, which are via Schottky-diode transitions coupled with the gates and the channel. With the help of this model we are able to explain the behavior of the electron waveguides.