Abstract
Current-voltage, capacitance-voltage-frequency characteristics, and impedance spectroscopy (IS) under conditions of reverse and forward bias are reported in Au/CdS/porous GaAs/GaAs devices. By comparing the C-V and C-f measurements, a possible existence of two depletion layers in our structure is discussed. In contrast to the typically expected parallel association of resistive and capacitive elements, an equivalent circuit is extracted from impedance plots, which employs the constant phase element and accounts for trap states and frequency dispersion. IS makes it possible not only to clarify the contribution of additional capacitive component due to the porous GaAs/GaAs interface by using an appropriate equivalent circuit model analysis but also to estimate a more reliable capacitance value of every junction in the structure. Published by AIP Publishing.