Broadband optical absorption measurement of silicon nanowires for photovoltaic solar cell applications

The broadband optical absorption properties of silicon nanowire films fabricated by electroless metal deposition technique followed by HF/Fe(NO 3 ) 3 solution-based chemical etching at room temperature on p-type silicon substrates have been measured and we have found higher absorption than that of the solid thin films of equivalent thickness. The observed behavior is effectively explained by light scattering and light trapping, though some of the observed absorption is due to a high density of surface states in the nanowire films. The synthesized structures absorbed more than 82% of incident radiation in case of Cu-deposited silicon nanowires, whereas for Ag it was a maximum of 83%, which is much greater than that of the bulk silicon as they absorbed a maximum of 43% of the radiation.