An Electrostatic Model of Split-Gate Quantum Wires

Abstract

We present a theoretical model of split-gate quantum wires that are fabricated from GaAs-AlGaAs heterostructures. The model is built on the physical properties of donors and of semiconductor surfaces, and considerations of equilibrium in such systems. Based on the features of this model, we have studied different ionization regimes of quantum wires, provided a method to evaluate the shallow donor density, and calculated the depletion and pinchoff voltages of quantum wires both before and after illumination. A real split-gate quantum wire has been taken as an example for the calculations, and the results calculated for it agree well with experimental measurements. This paper provides an analytic approach for obtaining much useful information about quantum wires, as well as a general theoretical tool for other gated nanostructure systems.