Washington, April 14 (ANI): Chemists at The Ohio State University have developed a technology for making a one-atom-thick sheet of germanium, and found that it conducts electrons more than ten times faster than silicon and five times faster than conventional germanium.
The material's structure is closely related to that of graphene-a much-touted two-dimensional material comprised of single layers of carbon atoms. As such, graphene shows unique properties compared to its more common multilayered counterpart, graphite.
Joshua Goldberger, assistant professor of chemistry at Ohio State and his colleagues describe how they were able to create a stable, single layer of germanium atoms. In this form, the crystalline material is called germanane.
Researchers have tried to create germanane before. This is the first time anyone has succeeded at growing sufficient quantities of it to measure the material's properties in detail, and demonstrate that it is stable when exposed to air and water.
In nature, germanium tends to form multilayered crystals in which each atomic layer is bonded together; the single-atom layer is normally unstable. To get around this problem, Goldberger's team created multi-layered germanium crystals with calcium atoms wedged between the layers. Then they dissolved away the calcium with water, and plugged the empty chemical bonds that were left behind with hydrogen. The result: they were able to peel off individual layers of germanane.
Studded with hydrogen atoms, germanane is even more chemically stable than traditional silicon. It won't oxidize in air and water, as silicon does. That makes germanane easy to work with using conventional chip manufacturing techniques.
The primary thing that makes germanane desirable for optoelectronics is that it has what scientists call a "direct band gap," meaning that light is easily absorbed or emitted. Materials such as conventional silicon and germanium have indirect band gaps, meaning that it is much more difficult for the material to absorb or emit light.
The first-ever transistors were crafted from germanium in the late 1940s, and they were about the size of a thumbnail. Though transistors have grown microscopic since then-with millions of them packed into every computer chip-germanium still holds potential to advance electronics, the study showed.
According to the researchers' calculations, electrons can move through germanane ten times faster through silicon, and five times faster than through conventional germanium. The speed measurement is called electron mobility.
With its high mobility, germanane could thus carry the increased load in future high-powered computer chips, Goldberger explained.
Next, the team is going to explore how to tune the properties of germanane by changing the configuration of the atoms in the single layer.
The study was published online in the journal ACS Nano. (ANI)
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