Black silicon: A new light absorber for photovoltaic applications

We demonstrate a new technique for texturing silicon surfaces using femtosecond laser pulses. Sharp micron-sized spikes are created by repeatedly irradiating a silicon surface with femtosecond laser pulses in the presence of SF6. The spikes are highly light-absorbing and enhance the light absorption in silicon close to 100 (increase in photocurrent of more than 60) over flat silicon. Spiked silicon is of potential use as a highly efficient light-absorber for solar cells and photodetectors.