Arizona State University researchers have created a new material that they say can be used to develop next-generation computers, improve the internet, increase the efficiency of silicon-based photovoltaic cells and improve solid-state lighting and sensor technology.
They've synthesized a single-crystal nanowire from a compound of erbium - used in doping optical fibers to amplify the signal.
"Since we could not dope as many erbium atoms in a fiber as we wish, fibers had to be very long to be useful for amplifying an internet signal. This makes integrating internet communications and computing on a chip very difficult," says electrical engineering professor Cun-Zheng Ning.
"With the new erbium compound, 1,000 times more erbium atoms are contained in the compound. This means many devices can be integrated into a chip-scale system. Thus, the new compound materials containing erbium can be integrated with silicon to combine computing and communication functionalities on the same inexpensive silicon platform to increase the speed of computing and internet operation at the same time.”
While erbium’s importance is well-recognized, producing erbium materials of high quality has been challenging, Ning says.
The standard approach is to introduce erbium as a dopant into various host materials, such as silicon oxide, silicon, and many other crystals and glasses.
What's unique about the new material is that erbium is no longer randomly introduced as a dopant. Instead, erbium is part of a uniform compound, meaning the number of erbium atoms is a thousand times more than the maximum amount that can be introduced in other erbium-doped materials.
Increasing the number of erbium atoms provides more optical activity to produce stronger lighting. It also enhances the conversion of different colors of light into white light to produce higher-quality solid-state lighting and enables solar cells to more efficiently convert sunlight in electrical energy.
In addition, since erbium atoms are organized in a periodic array, they do not cluster in this new compound. The fact that the material has been produced in a high-quality single-crystal form makes the optical quality superior to the other doped materials, says Ning.
Ning and his team are now testing the new erbium compound for various applications, such as increasing silicon solar cell efficiency and making miniaturized optical amplifiers for chip-scale photonic systems for computers and high-speed internet.
"Most importantly," he says, "there are many things we have yet to learn about what can be achieved with use of the material. Our preliminary studies of its characteristics show it has many amazing properties and superior optical quality. More exciting discoveries are waiting to be made."