Terahertz photocurrent spectrum analysis of AlGaAs/GaAs/GaAsBi multi-junction solar cells

Abstract Characterizing subcells in two-terminal multi-junction (M-J) solar cells is challenging due to the lack of direct electrical access. This work presents a novel contactless spectral characterization technique for analysing individual subcells. The involves probing terahertz (THz) radiation generated by femtosecond laser pulse excitation and varying exciting wavelength selectively absorb light desired subcell. registered THz integral then proportional induced photocurrent that spectroscopy demonstrated on GaAs AlGaAs single-junction cells, as well triple-junction AlGaAs/GaAs/GaAsBi cell. results show recently developed GaAsBi-based subcell, with nominal energy bandgap 1.0 eV, exhibits improved electron–hole separation efficiency can enhance harvesting M-J cells.