Boron-doped single crystal diamond features good electrical conductivity

Diamond is hailed as the "ultimate semiconductor material" due to its exceptionally wide bandgap, ultrahigh breakdown field, high melting point, and high thermal conductivity. Conventional superconductors are based on the BCS theory, which posits that superconductivity is formed by coupled phonons and electron Cooper pairs. The superconducting transition temperature is generally below 40K (approximately -233°C), known as the McMillan limit. However, some theoretical physicists suggest that unconventional high-temperature superconductors may be possible by utilizing excitons to couple electron Cooper pairs in carbon-based materials such as graphene.

Excitons are complexes of electrons and holes in semiconductors. Superconductivity indicates that a material achieves zero resistance and complete diamagnetic properties at a certain temperature. As a carbon-based semiconductor material, introducing excitons into diamond can achieve unconventional superconductivity.

By adjusting the pressure, temperature, and gas doping ratio during diamond growth, heavily doped diamonds can be produced that exhibit excellent electrical conductivity and a superconducting transition temperature of 3K (approximately -270°C). By adjusting the growth parameters of the buffer layer, samples with high hole mobility can achieve a superconducting state. This is due to the sufficient coupling of localized bound excitons with holes induced by boron doping, resulting in a superconducting state. The preparation of large-scale single-crystal superconducting diamond provides a solid foundation for the development of quantum sensing and quantum computing chips.

By transferring graphene onto the surface of boron-nitrogen co-doped single-crystal diamond to form a graphene/diamond heterojunction, new electrical transport behaviors similar to superconductivity are also realized in the graphene. At 27K (approximately -246°C), the resistance of the graphene was observed to begin decreasing, demonstrating the feasibility of achieving higher-temperature superconductivity in diamond and graphene. Currently, a new anode material with an ultra-high specific capacity exceeding 4500mAh/g for lithium battery anodes has been achieved. Efforts are now focused on the mass production of this material, which is expected to significantly increase the driving range of lithium-ion battery products such as new energy vehicles.

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.