Maskless fabrication of selectively sized silicon nanostructures for solar cell application

A two-step maskless method was used to synthesize silicon nanostructures. In the first step, silver nanoparticles were formed through rapid thermal annealing of silver thin films. The temperature, duration of annealing, and initial thickness of the silver film jointly determined the distribution and diameter of silver particles. In the next step, silicon nanostructures were created using silver catalyzed etching in HF/H₂O₂. The experiment confirmed that the final sizes of the nanostructures corresponded to the diameters of the silver particles. Further, silicon nanostructure-textured solar cells were manufactured and tested. The surface-reflection ratio of the cells can be decreased to 5% in the 300-1000 nm wavelength range. The current-voltage and quantum efficiency measurements also reveal that silicon nanostructure-textured solar cells exhibit considerable light trapping enhancement. The results also indicate that effective passivation and electrode contact are important for those cells.