Engineers Discover Gallium Nitride Has Diamond-like Wear Resistance

GaN Crystal.

A previously unknown property of the semiconductor material gallium nitride (GaN) has been discovered, thanks to research by a team of engineers from Lehigh University. To their surprise, the engineers discovered that the wear resistance of GaN is extremely high, approaching that of the famously robust diamond.

The Tribological Properties of Gallium Nitride

While GaN’s electronic and optical properties have been well-studied, no previous research has been done of its tribological properties; the material’s resistance to mechanical wear imposed by reciprocated sliding.

The engineers measured GaN’s wear rate using a custom microtribometer to perform dry sliding wear experiments. They found the wear rate of GaN ranges from 10^-9 to 10^-7 mm³/Nm, depending on certain factors such as environmental conditions and crystallographic direction. This wear rate approaches that of the most wear resistant material known, diamond, which ranges from 10^-10 to 10^-9 mm³/Nm (the lower the wear rate, the more wear resistant the material).

The researchers used a custom microtribometer (left) to determine the wear profile of GaN (right). (Image courtesy of Applied Physics Letters.)

As the engineers wrote in their paper on the experiments, they were taken aback with the extremely high wear resistance of GaN: "When performing wear measurements of unknown materials, we typically slide for 1,000 cycles, then measure the wear scars; [these] experiments had to be increased to 30,000 reciprocating cycles to be measurable with our optical profilometer.”

The Rise of GaN

This discovery has significant import for the electronics industry. GaN’s other properties already make it well-suited for many electronic applications, such as light-emitting diodes (LEDs), high temperature transistors, sensors and more. Now that its high wear resistance has been demonstrated, GaN may just become a star player in smartphones and other devices.

"Using GaN, you can build an entire device in a platform without multiple layers of technologies,” said researcher Nelson Tansu. “You can integrate electronics, light sensors and light emitters and still have a mechanically robust device. This will open up a new paradigm for designing devices. And because GaN can be made very thin and still strong, it will accelerate the move to flexible electronics."

Flexible electronics are already well on their way. Read New Memory Device Foreshadows Flexible Electronics for further insight.