Researchers create a technique to 'hear' flaws in promising nanomaterials

An international team from NYU Tandon and KAIST has developed a technique to identify atomic-scale defects in hexagonal boron nitride (hBN), a 2D material known as "white graphene."

This invention may hasten the creation of quantum and next-generation electronics.

According to the scientists, they were able to identify when boron atoms in hBN crystals were being replaced by individual carbon atoms. Listening to the electrical "noise" in specially constructed transistors—which is similar to hearing a whisper in a silent room—made this discovery feasible.

According to Yong-Hoon Kim and Davood Shahrjerdi, one of the paper's corresponding authors, they effectively developed a stethoscope for 2D materials with this effort. They were able to 'perceive' the behavior of individual atomic flaws by examining the minute and regular variations in electrical current.

The NYU-KAIST partnership, launched in September 2022, combines the strengths of both universities to drive research and education. The partnership currently involves over 200 faculty members. Single-crystal hBN, a wonder material, has the potential to transform fields from unconventional electronics to quantum technologies due to its atomically thin structure and excellent insulating properties. However, atomic defects in hBN can degrade its electronic properties, potentially harnessing them for quantum technologies.

The NYU researchers used layers of hBN sandwiched between an incredibly thin molybdenum disulfide, another 2D semiconducting material, to create a transistor. They observed distinct jumps in the current passing through the transistor by supplying exact electrical voltages and chilling this gadget to cryogenic temperatures.

These leaps, which are referred to as random telegraph signals (RTS), happen when hBN defects catch and release electrons. The team was able to identify the energy levels and spatial positions of the faults by closely examining these signals at various voltages and temperatures.