A NEW APPROACH TO THE MODELING OF GAAS ALGAAS NANOSTRUCTURES/

We present details of a new approach to the modelling of nanometre sca le devices which are based on the two-dimensional electron gas (2DEG) confined at the interface of a GaAs/AlGaAs heterostructure. The model, which is based on a finite difference solution to the Poisson equatio n, uses a Fang-Howard variational function to describe the 2D electron wavefunctions, and includes the effects of both a laterally and a ver tically inhomogeneous distribution of ionized donor impurities. A self -consistent method of adjusting the boundary conditions is employed to calculate the effect of an additional bias voltage. We apply our tech nique to the relatively simple case of a single-barrier lateral tunnel ling diode. Calculated current-voltage (I-V) characteristics are in ex cellent agreement with measured data using only the experimentally det ermined barrier height as a fitting parameter. Although our discussion is limited to a specific structure, we suggest that our method is app licable to a wide range of heterostructure devices.