Next to silicon, germanium (Ge) is the most widely used semiconductor material in the world. But while it’s great at conducting electricity, its inefficiency at turning light into electricity (or electricity into light) restricts the other applications for which it can be used.
Paul Simmonds, an assistant professor with a dual appointment to the departments of physics, and materials science and engineering, wondered if there was a way to fine-tune germanium’s physical properties, and thus improve its optoelectronic characteristics (how well it interfaces between electronics and light).
The Air Force Office of Scientific Research also was intrigued and funded a proposal titled “Optoelectronic Properties of Strain-Engineered Germanium Dots” with a three-year, $622,000 grant. Simmonds is working on the project through a sub-award administered through the University of California, Merced, and the University of California, Los Angeles. Boise State’s share of the award is $206,000.
“If we can turn Ge into an optoelectronic material, then other characteristics would make it attractive as a laser material,” Simmonds said. “It’s a bit like alchemy. We hope to change the fundamental properties of an element on the periodic table simply by stretching it a little.”
For years, scientists have tried putting germanium under tensile strain (stretching it at the atomic level) in order to improve its optoelectronic properties. But germanium is fragile, and crystalline imperfections cause it to break before enough tensile strain can be built up.
Simmonds and his research team have responded to the challenge by developing a new family of self-assembled nanomaterials capable of storing large amounts of tensile strain, without damage to the crystalline structure.
“Self-assembly has allowed us to develop a way for the materials to sustain high tensile strains without falling apart,” Simmonds said. “Instead of remaining flat, the atoms rearrange to form nanoscopic islands, like raindrops on the top of a car but about a million times smaller. The process of rearranging into 3D islands relieves a little of the strain and creates a window that allows us to have high tensile strain without breaking any atomic bonds. We’ve shown this works with other materials and now we want to try it with germanium.”
Doing so would help establish tensile self-assembly as a novel means by which to integrate dissimilar materials and demonstrate to the research community that nanostructure band engineering with tensile strain is an effective tool for discovering and designing materials for technological innovation.
While their work has real-world applications — creating direct band gap Ge nanostructures would be a critical breakthrough in optoelectronic materials research — Simmonds is excited that it’s also an opportunity to simply understand the world a little better.
Nucleic Acid Memory Holds Promise of Longer, Better Data Storage
A group of Boise State researchers, led by associate professor of materials science and engineering and associate dean of the College of Innovation and Design Will Hughes, is working toward a better way to store digital information using nucleic acid memory (NAM).
It’s no secret that as a society we generate vast amounts of data each year. So much so that the 30 billion watts of electricity used annually by server farms today is roughly equivalent to the output of 30 nuclear power plants.
And the demand keeps growing. The global flash memory market is predicted to reach $30.2 billion this year, potentially growing to $80.3 billion by 2025. Experts estimate that by 2040, the demand for global memory will exceed the projected supply of silicon (the raw material used to store flash memory). Furthermore, electronic memory is rapidly approaching its fundamental size limits because of the difficulty in storing electrons in small dimensions.
Hughes, with post-doctoral researcher Reza Zadegan and colleagues Victor Zhirnov (Semiconductor Research Corporation), Gurtej Sandhun (Micron Technology Inc.) and George Church (Harvard University), is looking to DNA molecules to solve the problem. Nucleic acid — the “NA” in “DNA” — far surpasses electronic memory in retention time, according to the researchers, while also providing greater information density and energy of operation.
Founded in 1932 by the Episcopal Church, it became an independent junior college in 1934, and has been awarding baccalaureate and master’s degrees since 1965. With nearly 23,000 students, Boise State has the largest enrollment of higher education institutions in the state of Idaho.
Boise State offers 201 degrees in 190 fields of study and has more than 100 graduate programs, including the MBA and MAcc programs in the College of Business and Economics; Masters and PhD programs in the Colleges of Engineering, Arts & Sciences, and Education; and the MPA program in the College of Social Sciences & Public Affairs.
Defying 30 mph gusts and temperatures down to minus 22 F,NASA’s new polar rover recently demonstrated in Greenland that it could operate completely autonomously in one of Earth’s harshest environments.
The robot known as GROVER, which stands for both Greenland Rover and Goddard Remotely Operated Vehicle for Exploration and Research, was designed by teams of students attending engineering boot camps at Goddard in the summers of 2010 and 2011. Built to carry a ground-penetrating radar to analyze layers of snow and ice, the rover was later transferred to Boise State University for fine-tuning with NASA funding.
Although researchers had tested GROVER at a beach in Maryland and in the snow in Idaho, the May 6 to June 8 testing at Summit Camp, the highest spot in Greenland, was the rover’s first polar experience. One of the main goals was proving that the robot could execute commands sent from afar over an Iridium satellite connection – an objective GROVER accomplished.
“When we saw it moving and travelling to the locations our professor had keyed in from Boise, we knew all of our hard work had paid off,” said Gabriel Trisca, a graduate student from Boise State University who has been involved in the GROVER project from its start. “GROVER has grown to be a fully-autonomous, GPS-guided and satellite-linked platform for scientific research.” Trisca accompanied the robot to Greenland.