C-VCalculations in CdS/CdTe Thin Films Solar Cells with aCdSxTe

Abstract

In CdS/CdTe solar cells, chemical interdiffusion at the interface gives rise to the formation of an interlayer of the ternary compoundCdSxCdTe1-x. In this work, we evaluate the effects of this interlayer in CdS/CdTe photovoltaic cells in order to improve theoretical results describing experimentalC-V(capacitance versus voltage) characteristics. We extended our previous theoretical methodology developed on the basis of three cardinal equations (Castillo-Alvarado et al., 2010). The present results provide a better fit to experimental data obtained from CdS/CdTe solar cells grown in our laboratory by the chemical bath deposition (for CdS film) and the close-spaced vapor transport (for CdTe film) techniques.

C-V model of CdS/CdTe thin-film solar cells dependent on applied voltage frequency

“…The Capacitance-Voltage (C-V) graph is compared with the experimental results of the CdS/CdTe solar cells and previous theoretical models. For instance, Castillo et al [21,22] consider in their model a direct voltage and a constant electrical permittivity; however, in the present report, an alternating voltage which is more consistent with the experimental conditions, and a dependence on the electrical permittivity with the frequency of the applied voltage is also assumed. As a result, we obtained a better fitting to the C-V graph experimental data by using these premises as well as consistency for values of the discontinuity band and interface charge density, respectively.…”

“…( 7) and ( 14), the capacitance values have been obtained by varying the voltage in 0.05mV intervals. The parameters used in the calculation are based on the experimental data and parameters reported in previous works [21,22,26]. Figure 2 A Schottky barrier in the contacts exists for the applied voltage from 0 to 19 mV, inducing a non-ohmic behavior.…”