Nanomembranes promise new materials for advanced electronics

Posted on 06. Oct, 2011 by in Academic Departments, Annual Report, Issues, Materials Science and Engineering, Research

The camera in your phone collects light on silicon and translates that information into digital bits. One of the reasons those cameras and phones continue to improve is that researchers are developing new materials that absorb more light, use less power, and are less expensive to produce. Recent innovations by a team of materials science and engineering researchers now promise even greater opportunities in the growth of materials beyond silicon and other traditional semiconductors.

Materials Science and Engineering Research Assistants Deborah Paskiewicz and Boy Tanto, along with Scientist Donald Savage and Erwin W. Mueller Professor and Bascom Professor of Surface Science Max Lagally have developed a new approach for using thin sheets of semiconductor known as nanomembranes.

Controlled stretching of these membranes via epitaxy allows the team to fabricate fully elastically relaxed silicon-germanium alloy nanomembranes for use as growth substrates for new materials. The team grew defect-free silicon germanium layers on silicon substrates and then released the silicon germanium layers from the rigid silicon, allowing them to relax completely as free-standing nanomaterials.

The silicon germanium film is then transferred to a new host and bonded there. From this stage, a defect-free bulk silicon germanium crystal can be grown (something not possible with current technology), or the silicon germanium membrane can be used as a unique substrate to grow other materials.

Epitaxy, growth that controls the arrangement of atoms in thin layers on a substrate, is the fundamental technology underlying the semiconductor industry’s use of these new materials. By combining elements, researchers can grow semiconductor alloy materials with unique properties that make possible new kinds of sensors or high speed, low-power, efficient advanced electronics. It is the ability to grow them without detrimental defects that makes these alloys useful to the semiconductor industry. However, making high-quality crystals that combine two or more elements faces significant limitations that have vexed researchers for decades.

With this new method, researchers could develop better oscillators, sensors and optical devices that are important to the cell phones, cameras and computers we use everyday.UW crest

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