Doping Induced Properties of Nanocrystalline CVD Diamond Films and Particles

Diamond is a material that possesses a unique combination of extreme properties [1]. With the advent of thin nanocrystalline diamond (NCD) films and particles the research field has expanded quickly into novel areas where monocrystalline diamond doesn’t provide a cost-effective solution. Especially the possibility to dope these materials led to versatile pathways towards advanced device concepts making use of the unique extreme and tuneable properties of diamond. While boron doped NCD films have been available for quasi a decade, recent progress has also seen the advent of phosphorus doped NCD and boron doped nanoparticles [2,3].

This presentation will introduce the fabrication of heavily doped diamond films using boron and phosphorus and as dopants, leading respectively to p-type and n-type conducting films. Advanced transmission electron microscopy techniques, like aberration-corrected HRTEM, show that acceptor and donor atoms are well embedded within the grains. However, the granular nature of the material, based on the interplay between grains and grain boundaries, has a clear influence on the incorporation of the dopants, the (superconducting) transport behaviour, etc., fundamental effects which will be reviewed [4,5].

In the second part, an insight into possible applications will be given. For example, the p-type conductivity induced by the boron acceptor turns such films into novel hole conducting electrodes for dye-sensitized solar cell applications, as confirmed by photo-electrochemical measurements [6]. By selectively etching away part of the substrate, also ultra-thin NCD membranes can be fabricated. Such structures can serve as soft X-ray beam monitors, or highly sensitive pressure sensors due to a piezoresistive effect thought to be originating in the grain boundaries [7,8].

References:

[1] R.J. Nemanich, J.A. Carlisle, A. Hirata, K. Haenen, MRS Bulletin 39/6 (2014), 490-494.

[2] W. Janssen, S. Turner, G. Sakr, F. Jomard, J. Barjon, G. Degutis, Y.-G. Lu, J. D’Haen, A. Hardy, M.K. Van Bael, J. Verbeeck, G. Van Tendeloo, K. Haenen, Physica Status Solidi RRL 8/8 (2014), 705-709.

[3] S. Heyer, W. Janssen, S. Turner, Y.-G. Lu, W.S. Yeap, J. Verbeeck, K. Haenen, A. Krüger, ACS Nano 8/6 (2014), 5757-5764.

[4] S. Turner, Y.-G. Lu, S.D. Janssens, F. Da Pieve, D. Lamoen, J. Verbeeck, K. Haenen, P. Wagner, G. Van Tendeloo, Nanoscale 4/19 (2012), 5960-5964.

[5] G. Zhang, S.D. Janssens, J. Vanacken, M. Timmermans, J. Vacík, G.W. Ataklti, W. Decelle, W. Gillijns, B. Goderis, K. Haenen, P. Wagner, V.V. Moshchalkov, Physical Review B 84/21 (2011), 214517.

[6] W.S. Yeap, X.J. Liu, D. Bevk, A. Pasquarelli, L. Lutsen, M. Fahlman, W. Maes, K. Haenen, ACS Applied Materials & Interfaces 6/13 (2014), 10322-10329.

[7] K. Kummer, A. Fondacaro, F. Yakhou-Harris, V. Sessi, P. Pobedinskas, S.D. Janssens, K. Haenen, O.A. Williams, J. Hees, N.B. Brookes, Review of Scientific Instruments 84/3 (2013), 035105.

[8] S. Drijkoningen, S.D. Janssens, P. Pobedinskas, S. Koizumi, M.K. Van Bael, K. Haenen, Scientific Reports 6 (2016), 35667