Diamond is an extraordinary material with unique properties qualifying it for high-end applications in mechanics, optics and electronics. For its industrial use in high power electronics (keyword: renewable energies) or quantum technology (sensing or computing), high-quality single crystals in wafer size are needed like for silicon. Unfortunately, existing synthesis technology cannot provide these sample.

To remove this bottleneck, over 30 years diamond research at the University of Augsburg aimed at the development of an efficient concept for the synthesis of large area diamond single crystals via heteroepitaxial deposition from the gas phase. Heteroepitaxy is the oriented growth of a crystalline material on top of a foreign single crystal. The breakthrough was achieved in 2017 with our multilayer system Diamond/Ir/YSZ/Silicon (see schema) [1,2,3]. The shown diamond disc has 155 carat. Until today, this wafer has neither been reached nor outperformed by any other research team internationally.

We brought the technology successfully to the market by founding the startup Augsburg Diamond Technology GmbH

( https://www.audiatec.de ) – numerous former students found an interesting job there after finishing their thesis at EXPIV.

Research in the diamond group at the University is currently focused on the following major topics:

1. How can the density of structural defects (mainly dislocations) be further reduced?
   Concepts like epitaxial lateral overgrowth (ELO) or metal assisted termination (MAT) are now under investigation. The work comprises modification of existing crystals by etching and patterning followed by overgrowth in one of the available microwave plasma chemical vapor deposition (MPCVD) setups. Various analytical techniques are then applied to analyze the synthesized crystals (RBS, XRD, SEM, µ-Raman spectroscopy, photoluminescence, Laser microscopy).
2. What is the influence of the remaining defects on the electronic properties of the heteroepitaxial diamond crystals?
   Samples are equipped with different metal electrodes to facilitate photocurrent (PC) measurements or to perform thermally stimulated current (TSC) measurements. Simulations are done to analyze and interpret the acquired data.

[1] https://www.nature.com/articles/srep44462

[2] https://idw-online.de/de/news670029

[3] https://www.spiegel.de/spiegel/ein-physiker-aus-augsburg-zuechtete-den-weltgroessten-diamanten-a-1180516.html

For further details please contact:

Dr. Matthias Schreck

Group Leader Diamonds

Experimental Physics IV

Phone: +49 (0) 821 598-3401

matthias.schreck@physik.uni-ausburg.de