Study the Radiation Effect on the Photovoltaic Properties of Silicon Heterojunction Solar Cells

In this work, influence of electron irradiation on the photovoltaic properties of n-type silicon heterojunction solar cells has been investigated. It has been shown that when irradiated with electrons with a fluence of 5 × 1014 cm–2, a significant decrease in the quantum efficiency occurs at wavelengths of more than 600 nm, leading to a decrease in the short-circuit current from 33.1 to 22 mA/cm2 and the open-circuit voltage from 0.68 to 0.53 V, and at a fluence of 1 × 1015 cm–2 up to 18.25 mA/cm2 and 0.51 V, respectively. Also, from the load current-voltage characteristics, the values of the surface recombination velocity are ~16 cm/s before irradiation, ~500 cm/s at 5 × 1014 cm–2 and 580 cm/s at 1 × 1015 cm–2 have been calculated. Using the admittance spectroscopy, a defect with an activation energy of 0.18 eV and capture cross section of σn = 5 × 10–15 cm2 was detected in irradiated structures, which may probably be responsible for this behavior of characteristics, its concentration increases with increasing fluence.