Fabrication and antireflection properties of solar cells with pyramid–nanohole texture by caesium chloride lithography

Abstract

Pyramids and nanoholes are integrated together to form a micro–nano-texture on silicon surface in order to suppress reflection for silicon solar cell application. The nanoholes are formed by inductively coupled plasma (ICP) dry etching employing a nanoporous aluminum (Al) mask which is fabricated by caesium chloride (CsCl) nanoislands lift-off technique. Reflection of less than 4% can be reached by pyramid–nanohole texture, which is much lower than that from pure pyramids or nanoholes texture. Higher short circuit current density (Jsc) and photovoltaic conversion efficiency (PCE) are obtained for the solar cell with pyramid–nanohole texture due to its better antireflection. The average diameter and depth of the nanoholes affect the solar cell properties. The smaller and deeper nanoholes can suppress reflection a lot, but meanwhile, the formation of them means more crystal lattice defects generated from ICP etching. An optimized diameter of 800 nm and depth of 1 µm for the nanoholes are obtained in our experiments to get the best photovoltaic performance that is a PCE of 14.89% with a Jsc of 38.25 mA cm−2 and an open circuit voltage (Voc) of 544.8 mV.