Annealing effects on Cu(In,Ga)Se<sub>2</sub> solar cells irradiated by high-fluence proton beam
Jiro Nishinaga, M. Togawa, Masaya Miyahara, Kosuke Itabashi, Hironori Okumura, Masataka Imura, Yukiko Kamikawa, Shogo Ishizuka
Abstract
Abstract Radiation tolerance of Cu(In,Ga)Se 2 (CIGS) solar cells has been investigated using high-fluence proton beam irradiation for application to devices in extremely-high-radiation environments. CIGS solar cells deteriorated after high-energy proton irradiation with non-ionizing energy loss of 1 × 10 16 MeVn eq cm −2 , however, the CIGS solar cells could generate power after high-fluence irradiation. The ideality factors increased from 1.3 to 2.0, and series resistance increased, indicating that the concentration of recombination centers increased in CIGS layers. After heat-light annealing, the conversion efficiencies gradually recovered, and the recombination centers were confirmed to be partly passivated by annealing at 90 °C. The short-circuit currents for 10 μ m thick CIGS solar cells were recovered by dark annealing in the same manner as for 2 μ m thick CIGS solar cells. Dark annealing on irradiated CIGS solar cells has beneficial effects on passivate the recombination centers, even using thicker CIGS layers.