Radiation Hard Amorphous Nitride Based Solar Cell Coverglass Anti-reflective Coatings

Solar cells are typically protected from the environment by a coverglass that has good light transmission properties in the response region of the solar cell. Newer generations of multilayer solar cells are extending the response region from the UV into the infrared portion of the spectrum to increase the efficiency of the solar cells. This is critically important for space based solar cells where the electrical output per unit weight is paramount. Unfortunately, solar cell coverglass materials have not kept up with the improvements in solar cell spectral range. It is difficult to fabricate the anti-reflective coatings and index matching layers to be efficient over the wider wavelength region of the newer solar cells. In addition for satellite power, the high radiation environments common at certain earth orbits cause the solar cell coverglass to lose transmittance (darken) through the formation of color centers in the glass or oxide materials. In this program Nanohmics proposes to examine the use of amorphous wide-bandgap nitride coatings to improve the performance radiation-resistant solar cell coverglass material. The amorphous nitrides will be used as an anti-reflective and index matching interface layer for the solar cells with the intent of increasing their spectral absorption and efficiency.