Theoretical calculations of tunneling characteristics of the Gated Resonant Tunneling Diode (GRTD) aie obtained in low dimensionality using a scattering transfer matrix approach. In the bias conditions whereby the GRTD reaches zerodimension in the well region, we consider attractive and repulsive perturbation potential (Vsc) of impurity or defect scattering in emitter and well regions. We describe the scattering matrices using the presence of evanescent, or nonpropagating, modes in different lateral confinement structure. Numerical solutions to the twodimensional Poisson equation and the continuity equation are used to calculate the lateral depletion region and carrier concentrations by the finite difference method. Electron transport in doublebarrier structure is calculated by a selfconsistent approach.