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

We prepared In0.53Ga0.47As/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 gales. Our experiments show a remarkable asymmetry in the gate efficiency: negative gate voltages seem to be more efficient than positive ones, end the pinch-off voltage of the waveguide depends mainly on the more negative sf 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. (C) 1998 Elsevier Science Ltd. All rights reserved.