Wideband light scattering of periodic micro textured glass substrates for silicon thin-film solar cells

A glass texturing process was developed to enhance the light scattering in the wideband wavelength range for thin-film hydrogenated amorphous silicon solar cells. Periodic honeycomb structures were patterned on glass substrates by a simple photolithography and chemical wet-etching process using HF (10%) solutions.We investigated the optical properties of the textured glasses for various etching times (i.e., the statuses of the etching steps), which were characterized using optical measurements and finite-difference time-domain simulations. We found the reproducible texturing conditions for obtaining high transmittance and haze values, and the angular distribution measurements showed that the scattered light is diffracted and trapped within the solar cell. The textured glass substrates showed a maximum transmittance of 95.5% and a haze ratio of about 61% in the wideband wavelength range, and the finite-difference time-domain simulation expected a very high short-circuit current density of ~21.9 mA/cm² for a single-junction thin-film hydrogenated amorphous silicon solar cell employing the honeycomb textured glass substrates, which will be useful for developing high-performance thin-film hydrogenated amorphous silicon solar cells.