Investigation of the Monocrystalline Silicon Solar Cell Physical Behavior after Thermal Stress by AC Impedance Spectra

In this work, the DC measurements and AC measurements (impedance spectra) have been used to characterize the mono crystalline silicon solar cell (MSiSC). From the I-V characteristics under dark conditions for different temperatures (298-353K°) and by using the ARREHENIUS diagrams defined by Ln(I)=f(1/T)ǀv=const, we have obtained the barrier height Ψ (eV), ideal factor A, and the reverse saturation current I0 (A); using the double exponential model.The AC measurement impedance [X(ω)=f(R(ω))] has been employed to measure the parameters of the MSiSC such as: heterogeneity factor, β, DC resistance Rdc, the bulk resistance Rb, activation energy E (eV), donor density Nd (cm-3) and density states Ns (cm-2). The solar cell was exposed to thermal stress within the range (298-353K°), the diagram of complex impedance in the dark, was obtained. This plot give a semicircles arcs, their centers lie below the real axis R(ω), corresponding to the appearance of the depression angle (θ≠0) which allows to measure the heterogeneity factor, β (β=2θ/π) which is in good agreement with the Cole-Cole diagram. It is noted that, β, increases with temperature. The intersection of the circle arcs from the right with x axis (i.e. at very low frequency) gives Rdc, while the intersection from the left gives Rb, of the sample (i.e. at very high frequency).By using ARREHENIUS diagrams defined by Ln(c)=f(1/T) and Ln(f)=f(1/T), we have obtained the parameters E (eV), Nd (cm-3), and Ns (cm-2).