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 degrees) and by using the ARREHENIUS diagrams defined by Ln(I)4(1/T)vertical bar(v=const), we have obtained the barrier height Psi (eV), ideal factor A, and the reverse saturation current I-0 (A); using the double exponential model. The AC measurement impedance [X(omega))=4R(omega))] has been employed to measure the parameters of the MSiSC such as: heterogeneity factor, beta, DC resistance R-dc, the bulk resistance R-b, activation energy E (eV), donor density N-d (cm(-3)) and density states N-s (cm(-2)). The solar cell was exposed to thermal stress within the range (298-353K degrees), the diagram of complex impedance in the dark, was obtained. This plot give a semicircles arcs, their centers lie below the real axis R(omega), corresponding to the appearance of the depression angle (theta not equal theta) which allows to measure the heterogeneity factor, beta (beta=2 theta/7 pi) which is in good agreement with the Cole-Cole diagram. It is noted that, beta, increases with temperature. The intersection of the circle arcs from the right with x axis (i.e. at very low frequency) gives R-dc, while the intersection from the left gives R-b, 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)). (C) 2014 Elsevier Ltd.