3D SIMULATION OF GAAS ALGAAS QUANTUM-DOT POINT-CONTACT STRUCTURES/

We present simulation results for the activation barrier phi(0) and th e number of electrons N in a quantum dot structure that are obtained f rom the self-consistent solution of the 3D Schrodinger-Poisson problem . We observe an approximately linear rise in the electrostatic barrier phi(0) as a function of the gate bias once pinchoff occurs. There is an associated linear decrease in the number of the electrons in the do t region. Calculated values of phi(0) and N are in an agreement with t hose utilized in the energy balance analysis for similar structure inv estigated experimentally in connection with negative conductance behav iour. The simulation results also suggest that, if the dot area is too small, all particles may be depleted from the dot before the input an d output barrier forms, thus preventing the bistable operation.