3D simulation of GaAs/AlGaAs quantum dot point contact structures

We present simulation results for the activation barrier φ₀ and the number of electrons N in a quantum dot structure that are obtained from the self-consistent solution of the 3D Schrödinger-Poisson problem. We observe an approximately linear rise in the electrostatic barrier φ₀ as a function of the gate bias once pinchoff occurs. There is an associated linear decrease in the number of the electrons in the dot region. Calculated values of φ₀ and N are in an agreement with those utilized in the energy balance analysis for similar structure investigated experimentally in connection with negative conductance behaviour. The simulation results also suggest that, if the dot area is too small, all particles may be depleted from the dot before the input and output barrier forms, thus preventing the bistable operation.