Influence of shunt conduction on determining the dominant recombination processes in CIGS thin-film solar cells

We investigated the transport and photovoltaic properties of Cu(In1-xGax)Se2 (CIGS) thin-film solar cells. The shunt-current-eliminated diode current could be obtained from the current–voltage characteristics by subtracting the parasitic shunt leakage current from the total current. The temperature dependence of the open-circuit voltage, extracted from the shunt-eliminated (total) current, suggested that the recombination activation energy is comparable to (much less than) the CIGS bandgap. The low-temperature characteristics of the diode ideality factor supported bulk-dominated recombination in the same cell. This suggests that shunt-current subtraction can provide the proper diode parameters of CIGS solar cells. ► Transport and photovoltaic characterizations of CIGS thin film solar cells. ► Shunt-current-eliminated diode current obtained by subtraction of parastic current. ► Activation energy obtained from open-circuit voltage vs. temperature curves. ► Bulk-dominated recombination suggested by temperature dependence of the ideality factor.