ZnO(CdS)/CIS/Mo solar cells characterized by modulation capacitance voltage measurements

From modulation capacitance voltage (MCV) measurements we determined a voltage V_s of several hundred mV at the depletion region in CuInS₂ under PV generator and short circuit working conditions. In this solar cell type electron transport through shallow gap states in the CdS interlayer enhances interface recombination which increases the dark current. The CuInSe₂ solar cells show a different behaviour. In darkness, electron emission into the depletion region over a barrier of more than 500 mV was measured, and voltage losses while working as PV generator remain nearly constant below 60 mV. We interpret these results by a blocking CuInS₂/Mo contact and a band spike at the CdS/CuInSe₂ junction