Consequences for the Relation between Impedance and IMPS Spectra

Consequences for the Relation between Impedance and IMPS Spectra 

The quasi-Fermi-level concept makes it possible to quantitatively relate intensity-modulated photocurrent spectroscopy (IMPS) and impedance data as follows. 

According to Eq. (4.15), the relative quantum yield, (p, obtained by IMPS measurements is given by 

Since in the case of IMPS at an n-electrode, p is constant, Eq. (7.90) reduces 

In addition, the Faraday impedance at the p-type electrode is given by -l/eA pp Ai/p 

In Fig. 7.46 the modulation of photocurrent at an n-type electrode is illustrated. The electrode potential corresponds to the quasi-Fermi level of electrons (majority carriers), p . During the modulation of the light intensity p remains constant when 

7 Charge Transfer Processes at the Semiconductor-Liquid Interface 

---