Superconducting boron doped nanocrystalline diamond on boron nitride ceramics

With the advancement in diamond growth technology it is possible to grow diamond on variety of non-diamond materials. The diamond films are polycrystalline in nature but retain all superlative properties such as superhardness1, superconductivity2, high thermal conductivity3, high dielectric strength4 seen in single crystal diamond. Another material with excellent dielectric property is boron nitride. It can be formed into synthetic material which is machinable, making it very attractive of variety of applications. It is also known as white graphite due to its graphite like structure but unlike graphite it is an excellent electrical insulator. In this work we have grown diamond on boron nitride ceramic to enhance the dielectric strength of machined parts. Apart from that, the machinable ceramic can from an excellent template for porous diamond film for supercapacitor application5.
As a first step towards such applications we test one of the superlative properties, namely superconductivity, of the diamond on the ceramics. The ceramics were shaped into 10X10X0.5mm plates. We first measured the zeta potential of the ceramics to select the diamond seeds for the growth. The zeta potential of the ceramics were found to be negative and so a H-treated diamond seed solution with positive zeta potential was selected. Diamond was grown on the seeded ceramics using a microwave chemical vapour deposition system. The superconductivity of the sample was tested in Quantum Design Physical Properties Measurement System using Van der Pauw configuration. The diamond on the ceramics were imaged with scanning electron microscopy.  The film has a transition temperature close to 3.5K. It is clear from the results that it is possible to grow good quality diamond films on the boron nitride ceramics. Similar strategies can be applied for growth of diamond on other types of ceramics.

Research results based upon these data are published at http://doi.org/10.1039/C9NR02729G

References

¹ O.A. Williams, Diam. Relat. Mater. 20, 621 (2011).

² E.A. Ekimov, V.A. Sidorov, E.D. Bauer, N.N. Mel’nik, N.J. Curro, J.D. Thompson, and S.M. Stishov, Nature 428, 542 (2004).

³ T.R. Anthony, W.F. Banholzer, J.F. Fleischer, L. Wei, P.K. Kuo, R.L. Thomas, and R.W. Pryor, Phys. Rev. B 42, 1104 (1990).

⁴ E. Boettger, A. Bluhm, X. Jiang, L. Schäfer, and C. ‐P. Klages, J. Appl. Phys. 77, 6332 (1995).

⁵ S. Yu, N. Yang, H. Zhuang, S. Mandal, O.A. Williams, B. Yang, N. Huang, and X. Jiang, J. Mater. Chem. A 5, 1778 (2017).