Material defects become electronic superpower

Scientists have discovered hidden mechanisms that allow next-generation semiconductors to remain stable while supporting the opposite electric field, a discovery that could revolutionize everything from quantum computing to energy-efficient electronic devices.

A team led by engineers at the University of Michigan solved the fundamental mysteries of Wurtzite ferroelectric nitrides, a promising class of semiconductors that can store information in an electric field without breaking it apart.

“The woundzite ferroelectric nitrides were recently discovered and have a broad range of applications in memory electronics, RF electronics, acousto-electronics, microelectromechanical systems and quantum photos,” said Zetian Mi, the Pallab K. Bhattacharya Collegiate Professor of Engineering at the University of Michigan and co-corresponding author of the study published in Nature.

The researchers found that when these materials contain two opposite electropolarization polarizations (similar to the northern and southern ends of magnets in the same material), they form unique atomic-scale “cracks” at the boundary where these opposite forces meet.

This structural damage does not cause the material to fail, but creates suspended chemical bonds that are filled with electrons that perfectly balance the excess negative charges encountered by polarity. This balancing behavior not only prevents material decomposition, but also creates electronic highways with extraordinary properties.

“It’s a simple and elegant result – sudden polarization changes often cause harmful defects, but in this case, the damaged bond accurately provides the expense required to stabilize the material,” said Emmanouil Kiouupakis, a Michigan professor of materials science and engineering, and his colleagues.

The team used electron microscope to reveal that at opposite polarized gathering points, hexagonal crystal structures are usually clamped on several atomic layers. This creates broken bonds that hold electrons and can conduct electricity when needed.

Making this discovery particularly important is that these conductive pathways can be turned on and off, moved in the material, and adjusted by manipulating the controlled polarization of the electric field, making them ideal for next-generation electronic devices.

“These interfaces have unique atomic arrangements that have never been observed and are more exciting. Even more exciting, we observed that this structure might be suitable for the conductive channels in future transistors,” said Danhao Wang, a postdoctoral researcher and co-corresponding author.

The researchers immediately recognized the potential of creating field effect transistors that can support high currents (critical for high power and high frequency electronics), and now focused on building such devices.

The study helps explain why these materials don’t tear themselves apart when supporting the opposite electric field, thus solving the mystery that has plagued scientists since the first discovery of the material. The team’s breakthroughs can accelerate advanced signal conversion between more energy-efficient computers, ultra-professional sensors, and electrical, optical and acoustic forms.

The researchers show that they can create, move and eliminate these conductive pathways by applying specific voltages, opening up possibilities for completely new nanoscale electronic devices.

According to Kioupakis, it is particularly noteworthy that this charge balance mechanism appears to be common in all tetrahedral ferroelectrodes – a material category that attracts next-generation micropower applications.

The study was funded by the National Science Foundation, the Army Research Office and the University of Michigan School of Engineering, and built the equipment in the Lurie Nanofrication facility and conducted research at the Michigan Materials Characterization Center.