Influence of quantum-well structural parameters on capacitance-voltage characteristics

The effects of quantum well (QW) parameters on the apparent carrier distribution (ACD) are investigated using a self-consistent simulation and the capacitance-voltage (C-V) profiling techniques. The simulation results show that the change of position expectation value of two-dimensional electrons (Delta (x) over bar(2D)) completely determines the full width at half maximum (FWHM) of 100 K ACD peak of In0.23Ga0.77As/GaAs single QW for the well width t(w) greater than or equal to 125 Angstrom. The value of Delta (x) over bar(2D) is insensitive to the variation of conduction band offset Delta E-c for Delta E-c greater than or equal to 120 meV. The influence of the Debye averaging effects on the ACDs increases as the values of t(w) and Delta E-c are decreased. In multi-QW structure, the Debye averaging effects influence the FWHM of ACD peaks mostly in the first QW. Extraction of QW parameters directly from the measured C-V profile is finally discussed. (C) 1999 American Institute of Physics. [S0003-6951(99)02220-2].