Capacitance-Voltage Characterization Technique Adapted to Tandem Solar Cell

Cyril Léon (1) , Sylvain Le Gall (1) , Marie-Estelle Gueunier-Farret (1) , Aurore Brézard-Oudot (1) , Alexandre Jaffré (1) , Nicolas Moron , Laura Vauche (2) , Karim Medjoubi (2) , Elias Veinberg Vidal (2) , Christophe Longeaud (1) , Jean-Paul Kleider (1)

1 GeePs - Laboratoire Génie électrique et électronique de Paris
2 CEA-LETI - Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information

This paper presents a simple and non-destructive method to determine doping densities and built-in potential of subcells by adapting the well-known capacitance-voltage (C-V) technique to two-terminal (2T) tandem solar cells. Because of the electrical coupling between the two subcells in a monolithic 2T tandem solar cell the standard method using a Mott-Schottky plot (1/C 2 vs. V) cannot be applied. Using numerical modeling, it is demonstrated that, by under chosen illumination conditions where only one subcell can absorb the light, it is possible to explore the bias dependence of the capacitance and to extract the parameters of the other subcell if the appropriate frequency conditions are present. This method is experimentally applied to an AlGaAs/Si tandem cell and parameters of both AlGaAs and Si cells are extracted. Finally, the validity of that method is assessed by the very good agreement obtained when comparing the values extracted from our measurements on the tandem cell to those extracted from measurements on isotype cells and to the values targeted during the fabrication process of the AlGaAs/Si tandem solar cell.

Keywords: characterization; tandem; multi-junction; capacitance; electrical coupling; solar cell

Domains: Physics [physics]; Condensed Matter [cond-mat]; Materials Science [cond-mat.mtrl-sci]; Engineering Sciences [physics]; Micro and nanotechnologies/Microelectronics; Engineering Sciences [physics]; Electric power; Engineering Sciences [physics]; Optics / Photonic; Engineering Sciences [physics]; Materials

Cyril Léon, Sylvain Le Gall, Marie-Estelle Gueunier-Farret, Aurore Brézard-Oudot, Alexandre Jaffré, et al.. Capacitance-Voltage Characterization Technique Adapted to Tandem Solar Cell. 36th European Photovoltaic Solar Energy Conference and Exhibition, WIP, Sep 2019, Marseille, France. pp.638, ⟨10.4229/EUPVSEC20192019-3CO.8.3⟩. ⟨hal-02343918⟩