A*STAR scientists have produced a uniform nanoscale ripple pattern over a wide area on a silicon surface by scanning a femtosecond laser beam across it. Given that a rippled surface is much less reflective than a smooth surface, this simple innovation could enhance the efficiency of solar cells by boosting their ability to harvest more sunlight1.
The use of lasers to produce periodic surface structures is currently an area of intense research. Laser processing has the important advantage that it heats only the surface of a material, leaving underlying structures unaffected. However, many laser processing methods are limited: they can process only small areas and shallow ripples.