The aim of this study is to analyse the individual cells of a micromorph tandem solar cell by dark current-voltage characteristics and to study the e ffect of temperature on the individual subcells of the device, being amorphous silicon and microcrystalline silicon. Special focus is placed on studying the temperature-dependent voltage distribution between the subcells. Furthermore, a short study will be performed on the eff ect of bias voltage on the EQE characterisation of tandem solar cells.