Scientists at the University of Chicago have developed a method to bond diamond layers directly to materials compatible with quantum and conventional electronics. This advancement addresses a significant challenge in integrating synthetic diamond, known for its durability and thermal conductivity, into various devices without compromising its properties.
Assistant Professor Alex High from the University of Chicago's Pritzker School of Molecular Engineering highlighted the unique qualities of diamond: “Diamond stands alone in terms of its material properties, both for electronics—with its wide band gap, very best thermal conductivity, and exceptional dielectric strength—and for quantum technologies—it hosts nitrogen vacancy centers that are the gold standard for quantum sensing at room temperature.” However, he noted that as a platform, it has been difficult to work with due to its homoepitaxial nature.
The research team published their findings in Nature Communications. They demonstrated a technique to bond diamond with silicon, fused silica, sapphire, thermal oxide, and lithium niobate without using an intermediary substance. Co-author F. Joseph Heremans explained that this new approach overcomes previous difficulties: “Its raw physical properties tick a lot of marks that are beneficial to a lot of different fields. It was just very difficult to integrate with dissimilar materials until now.”
The method involves creating surface treatments on diamonds and carrier substrates to enhance bonding through an annealing process. First author Xinghan Guo described the process: “We make a surface treatment to the diamond and carrier substrates that makes them very attractive to each other... An annealing process enhances the bond and makes it really strong.”
Avery Linder compared traditional methods using bulk diamonds to making "a single grilled cheese sandwich with an entire block of cheddar." The new technique allows for bonding crystalline membranes as thin as 100 nanometers while maintaining their suitability for advanced applications.
Assistant Professor Peter Maurer emphasized the significance of this development in quantum bio-sensing: “This new work with diamond membranes bonding that Alex’s lab led has gotten around many of these issues and brings us an important step closer to applications.”
The researchers have patented their process and are working on commercializing it through the University of Chicago’s Polsky Center for Entrepreneurship and Innovation. High expressed hope that this innovation could lead to advancements similar to those seen in complementary metal-oxide semiconductors (CMOS) technology.
Funding for this research was provided by the U.S. Department of Energy Office of Science Q-NEXT center and the National Science Foundation.