Characterization of Cu(In,Ga)Se$₂$ Electrodeposited and Co-Evaporated Devices by Means of Concentrated Illumination

We present a new Cu(In,Ga)Se ₂ characterization tool: Cu(In,Ga)Se ₂ microcells. By creating pixels on a Cu(In,Ga)Se ₂ substrate, we are able to test electrically different locations. Moreover, because of the reduced size of the cells, (5-to 500-μm wide), heat and spreading resistance losses are made negligible, which make high flux characterizations available. We analyze current-voltage curves under high concentration to gain insight in the physical properties of Cu(In,Ga)Se ₂ cells. From our analysis, Cu(In,Ga)Se ₂ electrodeposited absorbers present resistivity fluctuations that are much more important than co-evaporated ones. These absorbers, as they present more electronic defects, are also more affected by the V _oc increase under intense fluxes, and the efficiency gains can be very significant: up to 6% absolute efficiency points at less than 50 suns.