Tailoring the Post-Etching of Room-Temperature-Fabricated H and Ti Co-Doped ZnO Films for Efficient Harvested Light Trapping

Abstract

Chemical etching is widely applied to texture the surface of sputter-deposited zinc oxide films for efficient light-scattering in silicon thin-film solar cells. Based on experimental findings from our previous studies, two types of experimental techniques, a combination of HCl/NaOH and NaOH/HCl etching modes as well as a multi-step etching process, were considered to improve the light-trapping ability of room-temperature-deposited H and Ti co-doped ZnO (HTZO) films. The effects of the employed experimental procedures on the optical, electrical, and morphological properties of the HTZO films were systematically investigated. After optimization, higher haze values of 96.2%, 90.6%, and 74% at 550 nm, 800 nm, and 1100 nm, as well as a higher average haze value of 90.1% in the range of 400–1100 nm were achieved, which are better than those of the reference conventional HCl-etched Al-doped ZnO (AZO), high-light-trapping AZO, and SnO2:F films. These findings reveal a method to develop high-performance ZnO films for the front electrodes in high-efficiency Si thin-film solar cells.