Capacitance-voltage characteristics of quantum well structures

The characteristics of the apparent carrier distribution (ACD) of quantum well (QW) structures are investigated using the self-consistent simulation and the capacitance-voltage (C-V) profiling techniques. The simulation results on the differential carrier distribution show that the change of position expectation value of two-dimensional electrons determines the full width at half maximum of 100 K ACD peaks when conduction band offset is Delta E-c=160 meV and the QW width t(w) is greater than 120 Angstrom. The contribution of Debye averaging effects to the ACD peaks becomes important as t(w) and Delta E-c values decrease and the temperature is increased. The influence of Debye averaging effects on ACD peaks appears differently according to the location of each well in multiple QWs. These results indicate that the extraction of QW parameters from the C-V profile should be done with caution.