Beyond the sparkle, diamonds have hidden talents. They shed heat better than any material, tolerate extreme temperatures and radiation and handle high voltages while wasting almost no electricity \u2014 ideal traits for compact, high-power devices. These properties make diamond-based electronics promising for applications in the power grid, industrial power switches and places with high radiation, such as space or nuclear reactors.<\/p>\n
Diamond\u2019s ability to quickly carry heat away from electronic components allows devices to handle large currents and voltages without overheating. This means smaller devices can be used to switch to high power in the grid or in industrial settings. Diamond\u2019s natural resistance to radiation and extreme temperatures could enable electronics to work reliably in places where traditional silicon devices fail.<\/p>\n
Researchers at the U.S. Department of Energy\u2019s (DOE) Argonne National Laboratory are harnessing these strengths as the foundation for powerful, next generation electronics.
\nHowever, despite all its advantages, diamond has yet to find widespread use in electronic devices. \u201cDiamond hasn\u2019t become a mainstream semiconductor material yet due to a few bottlenecks,\u201d explained Argonne materials scientist Anirudha Sumant. \u201cMost notable is the difficulty of n-type doping.\u201d<\/p>\n
N-type doping means adding a tiny amount of another element to the diamond crystal lattice, its internal scaffold. This supplies extra electrons for electrical conduction. In contrast, p type doping creates \u201choles\u201d that act like positive charges. When an n-type region meets a p-type region, they form a PN junction \u2014 a one-way gate for electric current and the heart of devices like diodes and transistors.<\/p>\n
\u201cIn microelectronics, you need a PN junction to make a device,\u201d said Sumant. \u201dDiamond has exceptional properties compared with other wide-bandgap materials, but efficient n-type doping at room temperature is a major problem.\u201d<\/p>\n
Wide-bandgap materials are special semiconductors that can handle more energy. This wider gap lets them work better at higher voltages and temperatures and in harsher environments than silicon-based electronics.<\/p>\n
One way scientists have tried to dope diamond is by adding phosphorus. However, diamond lattice is very rigid, and phosphorus atoms are large. This causes strain and defects in the material. In diamond, phosphorus holds its extra electron so tightly that, at room temperature, there isn\u2019t enough energy to free it. As a result, phosphorus doped diamond works well only at high temperatures, which limits its practical use.<\/p>\n
Another promising approach to dope diamond is heterointegration: combining two different materials. With the rise of two-dimensional (2D) materials, like graphene, which are one atom thick, researchers have become interested in stacking these with bulk materials like diamond.
\n\u201cI thought, why not integrate an n-type 2D material with p-type diamond? That could produce electrostatic doping and unlock interesting properties,\u201d Sumant said.<\/p>\n
Electrostatic doping is a way to change how a material conducts electricity without adding new atoms. Instead of mixing in chemical dopants, scientists use electric fields from a nearby layer or gate to \u201cpush\u201d or \u201cpull\u201d electrons into the material. This creates regions that behave like n-type or p-type, but without permanently changing the material\u2019s composition.<\/p>\n
At the Center for Nanoscale Materials, a DOE Office of Science user facility at Argonne, Sumant and his team discovered that stacking a thin, 2D layer of molybdenum disulfide, a well-studied 2D material, on diamond created the right conditions for charges to move at the interface. This made the diamond act as if it had been doped, without the usual challenges of chemical doping.<\/p>\n
With traditional doping, electrons are shared throughout the material. When voltage is applied, charges move and combine to create current. With heterointegration, something different happens. When a voltage is applied, electrons \u201ctunnel\u201d into the p-doped diamond, where they join with the holes.<\/p>\n
\u201cThis tunneling helps electrons and holes come together to produce current, allowing the device to work at room temperature,\u201d explained Akshay Wali, an Argonne post-doctoral fellow and lead author of a study describing these findings.<\/p>\n
\u201cJust by stacking a 2D material on diamond, we get performance numbers that haven\u2019t been seen before in diamond-based devices,\u201d Sumant added. \u201dIt\u2019s a new way forward for electronics.\u201d<\/p>\n
Because diamond is naturally resistant to heat and radiation, it can help protect the ultrathin 2D layer. These devices may stay stable and reliable even under demanding conditions that challenge conventional electronics. This could make them well-suited for use in environments where there is high heat, strong electrical currents, or radiation.<\/p>\n
Looking ahead, the Argonne team plans to test these diamond-based devices for radiation hardness and compatibility with standard electronics. They are also exploring other 2D materials to further improve performance.<\/p>\n