Thin-film silicon solar cells are often deposited on textured ZnO substrates. The solar-cell performance is strongly correlated to the substrate morphology, as this morphology determines light scattering, defective-region formation, and crystalline growth of hydrogenated nanocrystalline silicon (nc-Si:H). Our objective is to gain deeper insight in these correlations using the slope distribution, rms roughness (σ(rms)) and correlation length (lc) of textured substrates. A wide range of surface morphologies was obtained by Ar plasma treatment and wet etching of textured and flat-as-deposited ZnO substrates. The σ(rms), lc and slope distribution were deduced from AFM scans. Especially, the slope distribution of substrates was represented in an efficient way that light scattering and film growth direction can be more directly estimated at the same time. We observed that besides a high σ(rms), a high slope angle is beneficial to obtain high haze and scattering of light at larger angles, resulting in higher short-circuit current density of nc-Si:H solar cells. However, a high slope angle can also promote the creation of defective regions in nc-Si:H films grown on the substrate. It is also found that the crystalline fraction of nc-Si:H solar cells has a stronger correlation with the slope distributions than with σ(rms) of substrates. In this study, we successfully correlate all these observations with the solar-cell performance by using the slope distribution of substrates.
Doped microcrystalline silicon oxide (mc-SiO x :H) alloys attract significant attention as a functional material in photovoltaic devices. By using various advanced characterization methods, we have studied the relationship between optoelectronic properties, chemical composition, and structure of p-type mc-SiO x :H deposited by plasma enhanced chemical vapor deposition (PECVD). For a wide range of compositions with varying oxygen content, we show that the dominant components are Si and a-SiO 2 , while the fraction of suboxides is minor. The mc-SiO x :H material with sufficient oxygen content (x ¼ 0.35) exhibits an enlarged optical gap E 04 > 2.2 eV and sufficiently high dark conductivity >10 À6 S cm À1 ; the crystalline silicon fraction has a filament-like shape (with a typical width of around 10 nm) forming a branch-like structure elongated in the growth direction over several hundreds of nanometers.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.