Impedonce-frequency Characteristics of Photoconducfive Loyers

Abstract

Measurements of the small signal impedance of photoconductive layers have been made both in the light and in the dark over the frequency rang 0.001 Hz to 10 kHz.
The impedance in the rang 0.1 Hz to 10 kHz was measured with a a.c. bridge and for the frequencies lower than 0.1 Hz the measurements were achieved with the aid of Rissajious' figure method given by A.J. Baker and A.R.Piercy.
The results were obtained as an equivalent parallel resistance R_p and a capacitance C_p of the photoconductive layer. Impedance loci were plotted using equivalent series resistance R_sand reactance X_s converted from above parallel components.
The theory resulted in an equivalent circuit for a photoconductive layer and then each value of curcuit elements was determined empirically utilizing the parallel components or impedance loci descrived above.
Theoretical considerations were given on the basis of the equivalent circuits for the internal states of photoconductive films.