We employ an accurate one-dimensional, self-consistent quantum-mechanical-Poisson solver to derive parameters that enable the Poisson solver to accurately compute charge- or capacitance-voltage curves for use in two-dimensional solvers. We consider metal-oxide-semiconductor field effect transistors (MOSFETs), where we adjust gate work functions and oxide thicknesses and SiGe MOSFETs with spacer layers where we adjust gate work functions and the carrier densities in the spacer layers, For GaAs pHEMTs, InP lattice-matched high electron mobility transistors (HEMTs), SiGe HEMTs, double-heterojunction pHEMTs. AlGaN/GaN HEMTs and delta-doped MESFETs we adjust the Schottky barrier heights to shift pinchoff voltages.