Name That Nanomaterial

It's time for a little fun. Well, that is, if you consider marveling at modern-art-esque images of extremely small (i.e. on the order of billionths of a meter) materials fun. I do, so I'll assume I'm not alone here.

Take a gander at these two nano images produced at Brookhaven. What are they? Why don't you tell me? Post your best guesses below. The winner gets 10 BNL Nerd Points.* I'll post the answers tomorrow.

*Obligatory small print: No cash value. Cannot be used in lieu of a thesis defense, as payment for your graduate student, or as a bribe for that copy editor to hurry up with your story. Bummer.

UPDATE (7/14/10): The answers can now be found here.