Monolithic two-terminal hybrid a-Si:H/CIGS tandem cells
Copper-indium-gallium-di-selenide (CIGS) is the present record holder in lab-scale thin-film photovoltaics (TFPV). One of the problems of this PV technology is the scarcity of indium. Multi-junction solar cells allow better spectral utilization of the light spectrum, while the required current generation per layer is much lower, allowing much thinner absorber layers of CIGS. In this contribution we demonstrate working fabricated devices of CIGS bottom cells that are monolithically integrated with a hydrogenated amorphous silicon (a-Si:H) top cell. The proposed structures are a unique fusion of two distinct fabrication methods, being co-evaporation and plasma enhanced chemical vapor deposition (PE-CVD). In addition, devices without any ZnO have been processed. In those cells a nc-SiOx:H n-layer acted as an electron recipient and lateral insulator for the CIGS p-layer, and a highly p- and n-doped nc-SiOx:H layer served as the tunnel recombination junction. The top TCO on the a-Si:H cell was varied with ZnO:Al (AZO) and In2O3/Sn2O3 (ITO). Efficiencies of the not yet optimized devices have reached 7.9% active area efficiency (with Voc=1.23V, FF=64%, Jsc= 9.95 mA/cm2).
To reference this document use:
TFT - Thin Film Technology
TS - Technical Sciences
Plasma enhanced chemical vapor deposition
Hydrogenated amorphous silicon
Thin film photovoltaics
Tunnel recombination junctions
Multi-junction solar cells
Institute of Electrical and Electronics Engineers Inc.
43rd IEEE Photovoltaic Specialists Conference, PVSC 2016. 5 June 2016 through 10 June 2016, 611-614