Superconducting Breakthrough in Boron-Nitrogen Codoped Single-Crystal Diamond Semiconductors

In the broad field of materials science, diamond is hailed as the "ultimate semiconductor material" due to its unique physical properties. Its ultra-wide bandgap, ultra-high breakdown field strength, high melting point, and excellent thermal conductivity endow diamond with enormous application potential in fields such as electronic devices, quantum computing, and high-temperature superconductivity. Using a self-developed microwave plasma chemical vapor deposition (MPCVD) system, we have successfully fabricated bulk single-crystal diamond semiconductors codoped with boron and nitrogen. Through mobility regulation, we achieved the superconducting state and metallic state of diamond, opening up a new path for the research on higher-temperature superconductivity in carbon-based materials.

The theoretical basis of traditional superconductors is the BCS theory, which holds that phonons couple electron Cooper pairs to form superconductivity. However, the superconducting transition temperature is generally below 40 K (approximately -233 degrees Celsius), a limitation known as the McMillan limit. With the continuous development of materials science, theoretical physicists have proposed using excitons (complexes formed by electrons and holes in semiconductors) to realize coupled electron Cooper pairs in carbon-based materials such as graphene, which may lead to the development of unconventional high-temperature superconductors. As a representative carbon-based material, the exploration of diamond's superconducting properties has naturally become a research focus.

By introducing excitons into diamond, an unconventional superconducting state is achieved, thereby breaking through the temperature limitations of traditional superconducting materials. This research is not only of great significance for understanding the superconducting mechanism of carbon-based materials, but also provides a solid material foundation for the development of cutting-edge technologies such as quantum sensing and quantum computing chips.

In the MPCVD system, by adjusting parameters such as pressure, temperature, and gas doping ratio during the growth process, bulk single-crystal diamond semiconductors codoped with boron and nitrogen were successfully prepared. The codoping of boron and nitrogen not only modifies the electronic structure of diamond, but also significantly enhances its electrical conductivity. Through the optimization of growth processes, the research team obtained heavily doped diamond samples with excellent conductivity, laying the groundwork for subsequent superconducting experiments.

To realize the superconducting state of diamond, the growth parameters of the buffer layer were further adjusted. It was found that samples with higher hole mobility could achieve the superconducting state. This discovery is attributed to the sufficient coupling between locally bound excitons and holes induced by boron doping, which in turn enables the superconducting state. Experimental results show that the superconducting transition temperature of this superconducting diamond sample is 3 K (approximately -270 degrees Celsius), and this result partially confirms the feasibility of the excitonic superconductivity mechanism.

This research has not only successfully achieved the superconducting state of diamond, but also partially verified the feasibility of the excitonic superconductivity mechanism. This discovery provides a new perspective for understanding the superconducting mechanism of carbon-based materials and offers new ideas for the research of high-temperature superconducting materials in the future.

The temperature limitation of traditional superconducting materials has long been a crucial factor restricting their applications. This research provides a new pathway for carbon-based high-temperature superconductivity, holding promise for advancing the application of superconducting materials in fields such as quantum computing and quantum sensing. Furthermore, the findings of this study also offer valuable insights for the research on superconductivity in other carbon-based materials like graphene.

Graphene was transferred onto the surface of boron-nitrogen codoped single-crystal diamond to fabricate a graphene/diamond heterojunction. Experimental results show that the resistance of graphene begins to decrease at 27 K (approximately -246 degrees Celsius), demonstrating the feasibility of achieving higher-temperature superconductivity in both diamond and graphene. This discovery opens up a new direction for the research on superconductivity in two-dimensional materials such as graphene.

In addition, with the rise of emerging industries including the Internet of Things (IoT), artificial intelligence (AI), and big data, higher requirements—such as high sensitivity, self-driven operation, and high efficiency—have been imposed on next-generation optoelectronic and power generation device systems. In summary, the breakthrough in the research on superconductivity in boron-nitrogen codoped single-crystal diamond semiconductors not only introduces a new research focus in the field of materials science, but also injects fresh impetus into technological progress in China and around the world. We have reason to believe that in the near future, carbon-based high-temperature superconducting materials will exhibit broader application prospects in fields such as quantum computing and quantum sensing.

The boron-doped single-crystal diamond produced by CSMH can achieve doping from low concentration to high concentration. It has realized a uniform and controllable concentration and a customizable boron doping process.CSMH uses the MPCVD method to prepare large-sized and high-quality diamonds,and currently has mature products such as diamond heat sinks, diamond wafers, diamond windows,diamond hetero junction integrated composite substrates,etc.