Etching effect of CdTe absorber on the stability of thin film solar cell devices

Cu seems to be necessary to achieve best efficiencies, however it is strongly connected with performance degradation due to its tendency to diffuse. The Cu benefits and drawbacks are still not completely clear. Other studies have shown a direct connection between Cu and defects concentration, however it is still not clear if the Cu induced degradation is due to a compensation or enhanced recombination due to the formation of new defects in bulk CdTe. Within this study many samples with Cu/Au back-contact have been prepared with different etching processes applying thermal, luminous and electrical stresses. We have analyzed the aging effects of those stresses by means of current-voltage, capacitance-voltage, drive level capacitance profiling characterization techniques.