Engineering Professor Conducts Explorations on the Nanoscale
Petra Reinke, Associate Professor, Department of Materials Science and Engineering
Just about every assumption made about the materials of everyday life start to collapse when objects become very small. At the micron scale—one-millionth of a meter—they retain their familiar properties. But in moving to the nanoscale—dimensions measured in billionths of a meter—strange things start to happen. Notoriously inert elements like platinum or gold become potent chemical catalysts, and gold turns into a liquid at room temperature. Normally stable, aluminum becomes combustible, and copper becomes transparent.
It is a fascinating and largely unknown world. However, it is one that must be mastered to continue producing smaller and more powerful electronic and mechanical devices. For Petra Reinke, associate professor in the Department of Materials Science and Engineering, the goal is to be able to engineer materials and construct structures that perform in predictable ways at the nanoscale.
Professor Reinke’s approach is to use a surface as a template. By varying this template, she can control the size and the organization in space of different nanomaterials layered on it, determining their properties and interactivity. “My aim is to unravel the relationship between nanoscale structure and properties at a surface,” she said.
Currently, silicon is the material of choice for semiconductors, but spintronics, which uses the spin of electrons rather than their charge, is the latest basis for a new generation of devices that will be much smaller, more versatile, and more robust. Realizing the promise, spintronics will require the ability to fabricate and manipulate ferromagnetic semiconductors, which combine silicon with materials that have magnetic properties at the nanoscale.
One of these materials is manganese. But creating manganese structures on silicon has proven difficult. In her work, Professor Reinke places a layer of manganese under a layer of silicon, applies heat, and, using tools like scanning probe microscopy and photoelectron spectroscopy, characterizes the structures that form at different temperatures. Her work has applications for organic solar cells, which offer an alternative to conventional silicon-based technology that is expensive, brittle, and difficult to fabricate.
Given what remains to be discovered at the nanoscale, Professor Reinke is very much an explorer. An advantage of her position is that all her observations, even those that do not suit her immediate purpose, provide important clues to the phenomena that shape this tiny world.