Current Research Projects

Diamond Electronics

Project leader: Prof. Jan Isberg
Researcher: Johan Hammersberg
Post Docs.: Dr Florian Burmeister, Dr Saman Majdi
Ph.D. student: Kiran Kumar Kovi, Nattakarn Suntornwipat
Alumni: Dr. Markus Gabrysch now at CERN, Geneva, Switzerland.

Diamond as a semiconductor

Diamond is a semiconductor with extreme properties, such as high breakdown field, high saturation velocity, high carrier mobilities and the highest thermal conductivity of all materials. This makes diamond extreme in the group of wide-bandgap semiconductors, which includes e.g., silicon carbide (SiC) and gallium nitride (GaN). Diamond electronic devices, such as power diodes and high-frequency field effect transistors, could in principle deliver outstanding performance due to diamond’s excellent intrinsic properties. Other applications where diamond is expected to excel include radiation detectors, neutron detectors, X-ray optics, biological applications, photoconductive switches, IR sensors etc. It is considered to be the material for future power electronic devices and for extreme conditions.


CVD Diamond

                 A single crystal CVD diamond plate.

Diamond synthesis can be achieved through several routes. The two main methods are high-pressure high-temperature synthesis (HPHT) and chemical vapour deposition (CVD). HPHT diamond is commonly used today in many industrial applications including: cutting, drilling, thermal management etc. However, HPHT diamond invariably contains many crystal defects and impurities. CVD diamond, on the other hand, can be grown under conditions of high purity resulting in fewer impurities. Unfortunately, the deposition conditions have invariably resulted in polycrystalline material. It was only recently shown that it is possible to grow thick free-standing plates of high-purity single-crystal CVD (SCCVD) diamond by homoepitaxy. To a great extent the interest in high-purity SCCVD diamond has been driven by the desire to develop diamond as a semiconductor material for electronic device applications. To achieve high activation in a doped semiconductor it is necessary to have a low degree of compensation. For p-doped material, for instance, the amount of compensating donors (shallow or deep) must be kept to a minimum. This puts strict demands on the impurity concentration of the material. Successful p-doping of diamond by adding boron during deposition has been demonstrated. Concentrations of nitrogen impurities < 1014 cm-3 have also been achieved, leading to low compensation levels.


Comparison of common semiconductor materials:
x-axis: Bandgap;  y-axis: Combined electron + hole mobility;
Area of circles proportional to thermal conductivity.


On going projects

  • Diodes / Breakdown
  • Electronic devices based on SC-CVD diamond
  • Transport in SC-CVD diamond
  • Defects in diamond
  • Infrared sensors based on diamond
  • Biological applications based on diamond substrates
  • Graphene on diamond substrates

Completed projects


Research areas:

Saman Majdi: Characterization of Diamond Properties, mainly DLTS Investigation of Diamond, Transport in SC-CVD diamond, IR sensors.

Kiran Kumar Kovi: Diodes/Breakdown studies, Graphene on diamond, Transport properties, Biological applications of diamond.


Jan Isberg, Markus Gabrysch, Johan Hammersberg, Saman Majd, Kiran Kumar Kovi, Daniel J. Twitchen, "Generation, transport and detection of valley-polarized electrons in diamond", Nature Materials 12, 760–764 (2013)

Saman Majdi, Kiran K. Kovi, Johan Hammersberg, Jan Isberg, "Hole transport in single crystal synthetic diamond at low temperatures", Appl. Phys. Lett. 102, 152113, 2013, doi: 10.1063/1.4802449

Henrik Löfås, Anton Grigoriev, Jan Isberg, and Rajeev Ahuja, "Transport coefficients in diamond from ab-initio calculations", Appl. Phys. Lett. 102, 092106, 2013, doi: 10.1063/1.4794062

Richard S. Balmer, Ian Friel, Steven Hepplestone, Jan Isberg, Michael J. Uren, Matthew L. Markham, Nicola L. Palmer, James Pilkington, Paul Huggett, Saman Majdi, and Richard Lang, "Transport behavior of holes in boron delta-doped diamond structures",
J. Appl. Phys. 113, 033702 (2013), doi:10.1063/1.4775814

Mahtab Ullah, E Ahmed, Ken Welch, Saman Majdi, N. R. Khalid, M. Ahmad, "Growth of Nitrogen-Incorporated Diamond Films Using Hot-Filament Chemical Vapor Deposition Technique", Advanced Science Letters, Volume 19, Number 1, January 2013 , pp. 291-295(5), doi:10.1166/asl.2013.4661

Jan Isberg, Markus Gabrysch, Saman Majdi and D.J.Twitchen,  "Negative Electron Mobility in Diamond",  Appl. Phys. Lett. 100, 172103 (2012); doi:10.1063/1.4705434

Markus Gabrysch, Saman Majdi, D. J. Twitchen, and Jan Isberg, "Electron and hole drift velocity in chemical vapor deposition diamond", Journal of Applied Physics 109, 063719 (2011). doi:10.1063/1.3554721

Jan Isberg, Markus Gabrysch, Saman Majdi, Kiran Kumar Kovi, and Daniel Twitchen,
"On the transition between space-charge-free and space-charge-limited conduction in diamond", Solid State Sciences 13, 1065-1067 (2011). doi:10.1016/j.solidstatesciences.2011.01.018

Kiran Kumar Kovi, Saman Majdi, Markus Gabrysch, Ian Friel, Richard Balmer and Jan Isberg, "Time-of-Flight Characterization of Single-crystalline CVD Diamond with Different Surface Passivation Layers",  MRS Proceedings, 1282, mrsf10-1282-a09-01, doi:10.1557/opl.2011.311

Henrik Löfås, Anton Grigoriev, Jan Isberg and Rajeev Ahuja, "Effective masses and electronic structure of diamond including electron correlation effects in first principles calculations using the GW-approximation", AIP Advances 1, 032139 (2011); doi:10.1063/1.3630932

Saman Majdi, Markus Gabrysch, Richard Balmer, Daniel Twitchen and Jan Isberg,
 "Characterization by Internal Photoemission Spectroscopy of Single-Crystal CVD Diamond Schottky Barrier Diodes"
, Journal of Electronic Materials, Volume 39, Number 8, August 2010, Pages 1203-1208 , doi:10.1007/s11664-010-1255-8

Jan Isberg, "Diamond Electronic Devices", Invited review article in "Proceedings of the European Materials Research Society, Symposium F: Wide Bandgap Semiconductors from Growth to Devices", Strasbourg, France, June 2010.

J. Isberg, S. Majdi, M. Gabrysch, I. Friel, R.S. Balmer,  "A lateral time-of-flight system for charge transport studies", Diamond and Related Materials, Volume 18, Issue 9, September 2009, Pages 1163-1166, DOI: 10.1016/j.diamond.2009.03.002

Margareta K. Linnarsson, J. Isberg, Adolf Schöner, Anders Hallén, "A Comparison of Transient Boron Diffusion in Silicon, Silicon Carbide and Diamond", Materials Science Forum (Volumes 600 - 603), Page(s):453-456, doi:10.4028/www.scientific.net/MSF.600-603.453

Jan Isberg, "Transport Properties of Electrons and Holes", Chapter 2 in "CVD Diamond for Electronic Devices and Sensors", ed. by R.Sussmann, John Wiley & Sons, Chichester, West Sussex. January 2009. ISBN: 978-0-470-06532-7.

Jan Isberg, "High Power Switching Devices", Chapter 12 in "CVD Diamond for Electronic Devices and Sensors", ed. by R.Sussmann, John Wiley & Sons, Chichester, West Sussex. January 2009. ISBN: 978-0-470-06532-7.

R S Balmer, I Friel, S M Woollard, C J H Wort, G A Scarsbrook, S E Coe, H El-Hajj, A Kaiser, A Denisenko, E Kohn, J. Isberg, "Unlocking Diamond’s Potential as an Electronic Material", Phil. Trans. R. Soc. A (2008) 366, 251–265, Abstract + Links

M. Gabrysch, S. Majdi, A. Hallén, M. Linnarsson, A. Schöner, D. Twitchen and J. Isberg,
“Compensation in boron-doped CVD diamond”
, physica status solidi (a) 205, No. 9, 2190-2194 (2008). doi:10.1002/pssa.200879711

M. Gabrysch, E. Marklund, J. Hajdu, D. J. Twitchen, J. Rudati, A. M. Lindenberg, C. Caleman, R. W. Falcone, T. Tschentscher, K. Moffat, P. H. Bucksbaum, J. Als-Nielsen, A. J. Nelson, D. P. Siddons, P. J. Emma, P. Krejcik, H. Schlarb, J. Arthur, S. Brennan, J. Hastings, and J. Isberg, “Formation of secondary electron cascades in single-crystalline plasma-deposited diamond upon exposure to femtosecond x-ray pulses”, Journal of Applied Physics 103, 064909 (2008).

J. Isberg, M. Gabrysch, A. Tajani, and D.J. Twitchen, “High-field Electrical Transport in Single Crystal CVD Diamond Diodes”, Advances in Science and Technology, Vol. 48 (2006) pp 73-76 http://www.scientific.net/3-908158-04-4/73/

J. Isberg, M. Gabrysch, A. Tajani, and D.J. Twitchen, “Transient current electric field profiling of single crystal CVD diamond”, Semicond. Sci. Technol. 21 (2006) pp 1193-1195 doi:10.1088/0268-1242/21/8/035

J. Isberg, A. Tajani, and D.J. Twitchen, “Photoionization measurement of deep defects in single-crystalline CVD diamond using the transient-current technique”, Phys. Rev. B 73, 245207 (2006) doi:10.1103/PhysRevB.73.245207

S.J. Rashid, A. Tajani, L. Coulbeck, M. Brezeanu, A. Garraway, T. Butler, N.L. Rupesinghe, D.J. Twitchen, G.A.J Amaratunga, F. Udrea, P. Taylor, M. Dixon, and J. Isberg, “Modelling of single-crystal diamond Schottky diodes for high-voltage applications”, Diam. Rel. Mater., Vol 15, Issue 2-3, (2006) pp 317-323.

J. Enlund, J. Isberg, M. Karlsson, F. Nikolajeff, J. Olsson, and D.J. Twitchen, Anisotropic dry etching of boron doped single crystal CVD diamond, CARBON, Vol 43/9, pp 1839-1842. doi:10.1016/j.carbon.2005.02.022

J. Isberg, A. Lindblom, A. Tajani, and D.J. Twitchen, “Temperature dependence of hole drift mobility in high-purity single-crystal CVD diamond”, Phys. Stat. Sol. (a) 202, No. 11, pp 2194-2198 (2005). doi:10.1002/pssa.200561915

S.J. Rashid, L. Coulbeck, A. Tajani, M. Brezeanu, A. Garraway, T. Butler, N.L. Rupesinghe, D.J. Twitchen, G.A.J. Amaratunga, F. Udrea, P. Taylor, M. Dixon, and J. Isberg, Numerical and Experimental Analysis of Single Crystal Diamond Schottky Barrier Diodes, Proceedings of the 17 International Symposium on Power Semiconductor Devices & IC's May 23-26, 2005 Santa Barbara, CA, pp 315-318.

J. Isberg, J. Hammersberg, D.J. Twitchen, and A.J. Whitehead, "Single Crystal Diamond for Electronic Applications", Diamond and Related Materials Vol 13/2 (2004) pp 320-324. doi:10.1016/j.diamond.2003.10.017 

J. Isberg, J. Hammersberg, H. Bernhoff, D.J. Twitchen, and A.J. Whitehead, “Charge collection distance measurements in single and polycrystalline CVD diamond”,
Diamond and Related Materials, Vol 13/4-8 (2004) pp 872-875.

D.J. Twitchen, A.J. Whitehead, S.E. Coe, J. Isberg, J. Hammersberg, T. Wikström, and E. Johansson, “High voltage single crystal diamond diodes”, IEEE Transactions on Electron Devices , vol 51, no 5 (2004) pp 826-828. doi:10.1109/TED.2004.826867

D.J. Twitchen, A.J. Whitehead, S.E. Coe, and J. Isberg, “Applications of Single Crystal CVD Diamond”, Proceedings of the Seventh Applied Diamond Conference/Third frontier Carbon Technology Joint Conference (ADC/FCT 2003) NASA/CP - 2003- 0 212319 p 111. http://gltrs.grc.nasa.gov/reports/2003/CP-2003-212319.pdf

J. Isberg, J. Hammersberg, E. Johansson, T. Wikström, D.J. Twitchen, A.J. Whitehead, S.E. Coe, and G.A. Scarsbrook, “High Carrier Mobility in Single-Crystal Plasma-Deposited Diamond”, Science Vol 297, September 2002, pp 1670-1672.

J. Hammersberg, J. Isberg, E. Johansson, T. Lundström, O. Hjortstam, and H. Bernhoff, “Injection dependent long carrier lifetimes in high quality CVD diamond”,
Diam. Rel. Mater., Vol 10, Issues 3-7, March-July 2001, pp 574-579.


The Diamond Electronics Project