N-type hydrogenated microcrystalline silicon oxide (μc-SiOx:H) layers were used as window layers in n-side illuminated microcrystalline silicon n–i–p solar cells. Optical, electrical and structural properties of μc-SiOx:H films were investigated by Photothermal Deflection Spectroscopy, conductivity and Raman scattering measurements. μc-SiOx:H layers were prepared over a range of carbon dioxide (CO2) flow and film thickness, and the effects on the solar cell performance were investigated. By optimising the μc-SiOx:H window layer properties, an improved short-circuit current density of 23.4 mA/cm2 is achieved, leading to an efficiency of 8.0% for 1μm thick absorber layer and Ag back contact. The correlation between cell performance and μc-SiOx:H layer properties is discussed. The results are compared to the performance of solar cells prepared with alternative optimised window layers.
Phys. Status Solidi C 7,1053–1056 (2010)