Copper-induced crystallization of sputtered silicon on ZnO:Al substrate and the textured interface for light trapping

摘要

Copper-induced crystallization of a-Si on ZnO:Al (AZO) substrate is studied. On Ar sputtered AZO substrate, the optimized crystallite and crystalline ratio of poly-Si are ~30nm and ~71%, respectively. O_2 is also introduced and optimized when preparing AZO substrates. On AZO substrate with O_2/Ar+O_2 =3%, the crystallite and crystalline ratio of poly-Si are greatly improved, showing ~40 nm and ~82%, respectively. Textured AZO is prepared for analyzing the light-trapping efficiency. With 40 s etching in 0.5% HC1, ~0.7 μm lateral scale and ~119 nm root mean square roughness is obtained. The scattering property is verified by the flat step over a large angle range in the angular distribution measurement. 660 nm Cu-induced poly-Si on this AZO substrate shows an average reflectivity of ~17.7%, only 45% of the flat Si, showing a good light-trapping efficiency and a potential use in solar cells.