Monocrystalline ZnTe/CdTe/MgCdTe double heterostructure solar cells grown on InSb substrates

Monocrystalline p-ZnTe/p-CdTe/n-CdTe/n-MgCdTe double-heterostructure (DH) solar cells are designed and demonstrated with a maximum efficiency of 10.9 %, an open-circuit voltage (V_OC) of 759 mV, a short-circuit current density (J_SC) of 21.2 mA/cm² and a fill factor (FF) of 67.4 %. The low efficiency is mainly due to the combination of the low VOC and FF, which are attributed to high interface recombination at the ZnTe/CdTe, and p-CdTe/n-CdTe interfaces. Activation energies (E_A) of 1.54 eV and 1.25 eV are obtained from temperature dependent light-IV measurements, indicating that the dominant recombination mechanism changes from interface recombination for non-annealed devices to bulk recombination for devices annealed at 450 °C.