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Abstract
In this paper, a study by simulation of the capacitance and conductance of carriers of a heterojunction composed of a layer of Zinc oxide (ZnO), a layer of cadmium sulphide (CdS) and a layer of CIGS under the influence of a potassium fluoride (KF) layer placed in the CIGS / CdS interface is made. The simulation done with the SCAPS-1D software. Measurements on the capacitance-tension, the conductance-tension, the capacitance-frequency and the conductance-frequency are taken. The capacitance-voltage measurement shows an increase in capacitance as a function of the voltage and a decrease in its module when the KF layer is present in the CdS / CIGS interface. The conductance-voltage measurement also shows an increase in the conductance as a function of the voltage and when the KF layer isn’t present. The capacitance-frequency measurement shows a constancy of capacitance for the low values of the frequency and a decrease for the large values of the frequency. While the conductance-frequency characteristic shows an increase in the conductance with the frequencies. The measurements conductance-frequency and capacitance-frequency show a decrease in their modules when the KF layer is put into the CdS / CIGS interface. Besides, the total capacitance and the total conductance of the solar cell are determined according to the thickness of the KF layer. The measures reveal aussi that the capacitance and the conductance decrease with the increase in the thickness of the KF layer. The decrease in capacitance is caused by a passivation of the interface states while that of the conductivity is caused by the increase of the resistivity of the CIGS layer.