Impacts of etching time on surface morphological and optical properties of nano-inverted pyramids on silicon fabricated using copper-assisted chemical etching

This study investigates the impacts of etching time on the surface morphology and optical properties of nano-inverted pyramids (NIPs) on monocrystalline silicon (mono c-Si) wafers using cost-effective copper-assisted chemical etching (CACE) process. By varying the etching time, we aim to optimize the texturing conditions to achieve the lowest average reflection and the highest broadband light absorption in the mono c-Si absorber within 300–1100 nm wavelength region. The results demonstrate that the etching time significantly influences the formation of the NIPs. After 7 min of etching, dense NIPs have been formed on the surface with root mean square roughness (RMS) roughness of 197 nm, leading to the lowest average reflection (Ravg) of 7.95% and the highest light absorption of 92.05%. Furthermore, the average absorption enhancement at wavelength of 600 nm improves significantly when compared to the planar mono c-Si (reference); 1.45 for 7 min of etching. The findings provide valuable insights into the development of NIPs by CACE process, paving the way towards realizing high-efficiency photovoltaic (PV) devices in the future.