Photoelectrochemical Impedance Spectroscopy: I . Validation of the Transfer Function by Kramers‐Kronig Transformation

The photoelectrochemical properties of n‐Si in with and without are explored using photoelectrochemical impedance spectroscopy to define a transfer function as the ratio between the modulated output voltage of a fast photodiode (proportional to the incident light intensity) and the modulated photocurrent response. We show that the transfer function transforms correctly according to the K‐K relations, demonstrating that the system satisfies the linearity, causality, and stability constraints of linear system theory. Accordingly, the transfer function may be identified with the system impedance and may be analyzed in terms of passive electrical analogs or reaction models that employ Heaviside algebra.