Improvement of Solar Cells Efficiency and Radiation Stability by Deposition of Diamond-Like Carbon Films

Diamond-like carbon films (DLC) deposited by PE-CVD technique were used as antireflection and protective coatings for Si and AB based solar cells (SC). Application of the DLC films as singleor doublelayer antireflection coatings allows us to improve the Si-based solar cells efficiency up to 1.4-1.5 times (from ~10% to ~15%). It has been shown that optical bandgaps of DLC films were increased after UV irradiation. The films with greater amount of nitrogen show better irradiation resistance. It was also established that Si (both monoand multicrystalline) and AB based SCs with even thin antireflection DLC film demonstrate higher stability against action of gamma-irradiation up to dose of 10 rad. The effect is connected with hydrogen atoms those are released from the film as a result of broken of carbon-hydrogen bonds by γor UV-quanta, diffuse to the SC, and passivate dangling bonds in the SC volume. It has been also shown that due to application of the DLC antireflection films with low refractive index the transparency of front ITO or ZnO (Al) contacts in AB based SCs may be substantially improved integrally to 10% in spectral range of 430-850 nm. As a result, short circuit current and efficiency of thin film SCs may be also improved.