Diamond, renowned for its extraordinary hardness and clarity, has become a standout material in high-power electronics and the innovative field of quantum optics. By adding impurities like boron, diamonds can be modified to conduct electricity as efficiently as metals.
Diamond, renowned for its extraordinary hardness and clarity, has become a standout material in high-power electronics and the innovative field of quantum optics. By adding impurities like boron, diamonds can be modified to conduct electricity as efficiently as metals.
Researchers from Case Western Reserve University and the University of Illinois Urbana-Champaign have uncovered a fascinating characteristic of boron-added diamonds, referred to as boron-doped diamonds. Their discoveries may lead to the development of advanced biomedical and quantum optical devices that are quicker, more efficient, and capable of processing information in ways that traditional technologies cannot. Their findings have been published today in Nature Communications.
The team found that boron-doped diamonds display plasmons—electron waves that are activated by light—enabling precise control and enhancement of electric fields at a nanoscale. This property is crucial for state-of-the-art biosensors, nanoscale optical instruments, and for optimizing solar cells and quantum devices. While boron-doped diamonds were already known for their electrical conductivity and potential for superconductivity, their plasmonic traits had not been previously recognized. Unlike metals or other doped semiconductors, boron-doped diamonds maintain their optical clarity.
“Diamond continues to shine,” stated Giuseppe Strangi, a physics professor at Case Western Reserve. “Both literally and as a guiding light for scientific and technological progress. As we delve deeper into the realm of quantum computing and communication, these discoveries bring us closer to fully exploiting materials at their core.”
Mohan Sankaran, a professor of nuclear, plasma, and radiological engineering at Illinois Grainger College of Engineering, remarked, “Understanding the impact of doping on the optical behavior of semiconductors like diamond enhances our comprehension of these materials.”
Plasmonic materials, which interact with light at the nanoscale, have fascinated people for centuries, even before the scientific principles were clear. The vivid colors seen in medieval stained-glass windows are the result of metal nanoparticles embedded in the glass. When illuminated, these particles produce plasmons that create distinct colors—gold nanoparticles yield a rich ruby red, while silver nanoparticles show a bright yellow. This historical artistry showcases the interplay between light and matter, paving the way for modern advancements in nanotechnology and optics.
Diamonds, made of transparent carbon crystals, can be created with trace amounts of boron, which is located next to carbon on the periodic table. Boron has one fewer electron than carbon, which allows it to accept electrons. This creates a periodic electronic “hole” that enhances the material’s conductivity. The boron-doped diamond structure remains transparent, exuding a blue tint—similar to the iconic Hope Diamond, which is blue due to boron’s minimal presence.
Thanks to its unique features—being chemically inert and biologically compatible—boron-doped diamonds could find uses in areas where other materials can’t, such as medical imaging and high-sensitivity biochips or molecular sensors.
The development of low-pressure synthesized diamonds was initiated at Case Western Reserve (then known as Case Institute of Technology) in 1968 by John Angus, a faculty member who passed away in 2023. Angus was also the first to report on the electrical conductivity of boron-doped diamonds.
Strangi and Sankaran collaborated with Souvik Bhattacharya, the lead author and a graduate student at Illinois; Jonathan Boyd from Case Western Reserve; Sven Reichardt and Ludger Wirtz from the University of Luxembourg; Vallentin Allard, Aude Lereu, and Amir Hossein Talebi from Marseilles University; and Nicolo Maccaferri from Umeå University in Sweden.
This research received support from the National Science Foundation.
