Solar cells based on DLC film – Si structures for space application

Significant increase in solar cell (SC) efficiency after the deposition of thin antireflection diamond-like carbon (DLC) films has been observed. Thick (1300–1500 nm) DLC films deposited on a working side of the SC allow us to increase their stability relating to the effect of proton and ultraviolet (UV) irradiation. So, one-stage (E=50 keV) or multi-energy (50+100 keV) implantation of proton into protected SC (the SC+DLC films system) did not practically influence the SC parameters. Moreover, SC covered by DLC film after UV irradiation show improvement of efficiency both for implanted and unimplanted samples. At the same time the unprotected SC deteriorated after those treatments.The effects observed are connected with the decrease in reflection losses due to the deposition of DLC films and self-annealing of radiation damages in implanted DLC films due to light-induced hydrogen bonding. Re-emission by DLC film of the absorbed ultraviolet light in visible spectral range was observed and mechanism of the effect was proposed. Application of nitrogen-doped DLC film as a fluorescent layer allows us to improve Si SC efficiency in UV spectral range. The results obtained have opened up a wide variety of potential applications of DLC films, especially for space solar cells.