US Patent 7884446 - Nanospikes

http://www.freepatentsonline.com/7884446.html

This patent from Harvard teaches a method of laser processing a silicon substrate to create a nanospiked surface. Claim 1 reads:

1. A semiconductor substrate, comprising a surface layer having at least a portion exhibiting an undulating topography characterized by a plurality of submicron-sized features having an average height less than about 1 micrometer and an average width in a range of about 100 nm to about 500 nm.