Forming random-micropores by optimized 2-step metal assisted etching process

Abstract

We present a reliable and cost effective 2-step metal-assisted-etching (MAE) texturing technique that forms random-micropores. The optical behavior of the random-micropores is systematically studied. We demonstrate that the random-micropore morphology is capable of suppressing front surface reflection more efficiently than not only the conventional acidic texturing but also the widely used random pyramid texture. We demonstrate that the angular reflectance distribution of our random-micropores is intermediate between isotexture and random upright pyramid structures. These results strongly suggest that the random-nanopore texture can outperform isotexture and random upright pyramid morphology when encapsulated. Due to its nano-scale feature size, it can be used for texturing both mono-crystalline (c-si) and multi-crystalline (mc-si) silicon solar cells, as well as non-conventional thin Si solar cells such as SLIVER cells that feature surfaces that cannot easily be textured using established texturing techniques. The uniformity and reproducibility of the morphology have also been verified.