A Material World

École Polytechnique de Montréal, in Canada

This color-enhanced scanning electron micrograph shows an array of CoFeB nanowires, grown by pulse-current electrodeposition in a nanoporous alumina template. During the electrodeposition process, some of the nanowires overflowed on the template surface. “It’s a reminder that nanoscale research can have unpredicted consequences at a high level,” Béron says.

IFW Dresden, Institute of Metallic Materials, in Germany

These Ni-Mn-Ga melt-extracted fibers were imaged with a backscattered electron detector in a field-emission gun scanning electron microscope. The fibers have an approximate diameter of 100 µm and a bamboo-like appearance. “Melt-extraction is a unique and novel method to prepare single-crystalline particles for magnetic shape memory composites,” Gutfleisch explains.

Johns Hopkins University

The tiny dice in this scanning electron micrograph were made using solder-based, surface tension-driven self-assembly. Leong likens the technique to rudimentary micro-origami, as it allows one to pattern 2D structures and then pop them up into 3D. “One of the big perks of this method is that it allows for easy patterning of the side faces of 3D structures, which is normally very difficult to do,” Leong says. “To highlight this flexibility, we patterned the pips of dice into the faces before folding them.” The result is a collection of gold-coated nickel dice 200 microns wide. The fuzziness of the dice is an accidental result arising from storing the dice in ethanol within polystyrene dishes, Leong notes. “Apparently, the polystyrene slowly dissolved and then formed a partial crust on the dice.”

Tallinn University of Technology, in Estonia

This scanning electron microscope image features a CuInSe2 film with crystalline Cu2Se plates and crystalline InSe needles on its surface.

Drexel University, Philadelphia

The picture shows a colored image of the layered steps formed inside closed pores of La0.8Ca0.2CoO3. The steps were revealed upon fracture of the material, Pathak says.

Princeton University

For this picture, two images were taken with a scanning tunneling microscope (STM) and superimposed using Adobe Photoshop. The sky portion is from an image of the organic molecule THAP (tris{2,5-bis(3,5-bis-trifluoromethyl-phenyl)-thieno} [3,4-b,h,n]-1,4,5,8,9,12-hexaazatriphenylene) deposited on Au(111) and subsequently exposed to a high background pressure of cobaltocene. “While THAP on Au(111) is normally very uniform and regularly ordered, exposure to cobaltocene disrupts the order and causes certain molecules to appear much darker in STM,” Ha says. The land portion is a 3D image of a hexaazatrinaphthylene deposited on Au(111). The compound arranges regularly on Au(111), and this appears as the evenly spaced bumps throughout the image. The spikes are clusters of multiple hexaazatrinaphthylene molecules, and the mesas are single atomic layer steps in the Au(111) substrate.