Press Releases

"21-05-2019:Original kilogram replaced -
New International System of Units (SI) entered into force on 20 May 2019"

In addition to Ampere, Kelvin, Mol and Co., the kilogram also is now defined by a natural constant. In concrete terms, this means that the original kilogram, which has been the measure of all things for 130 years, has now served its purpose in Paris. This is made possible by the single crystals grown from the highly enriched isotopic silicon-28 at the Leibniz-Institut für Kristallzüchtung (IKZ).

Si AnlagePrototype of a silicon-28 single crystal after growth in a floating zone plant in the context of the KILOGRAM project. (Source: IKZ)

The new International System of Units (SI) was adopted at the 26th General Conference on Weights and Measures in Paris on 16 November 2018. Now the system officially came into force on 20 May 2019, the World Metrology Day. From now on, 7 natural constants form the foundation of all measures.

Hereafter, a new definition for the kilogram is valid using the Planck constant and thus this unit is no longer determined through the mass of the „original kilogram“. The scientific and high-technology communities mostly benefit from this. The IKZ played a decisive role in replacing the almost 130-year-old artificial object of the original kilogram, because the structurally perfect crystals of isotopically-pure silicon-28 (28Si, enrichment up to 99.9995 %) grown at the IKZ were of decisive importance for this project.

In these crystals, almost all the atoms have the same mass and are arranged in a regular three-dimensional lattice, which makes a very exact assignment possible between the mass of the crystal and the number of its atoms. From this relation, the value of the Avogadro constant could be derived with unprecedented precision and thus used as a fundamental natural constant for the definition of the kilogram, since the Plank constant could be determined more precisely with the help of the Avogadro constant. In the new SI system, the value of the Avogadro constant is determined and one mole therefore contains exactly 6.02214076×1023 individual particles.

But that is not everything. Now all 7 basic units are defined by natural constants. This has been the case for many years for the second (with the hyperfine structure transition of the ground state in the Cs atom), the metre (via the speed of light) and the candela (via the photometric radiation equivalent of a special radiation). Now the other units also follow, whereby here the elementary charge (for the ampere), the Boltzmann constant (for the Kelvin), the Avogadro constant (for the mole) and the Planck constant (for the kilogram) play the decisive roles.

IWithin the framework of the "KILOGRAM" projects led by the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig, several very precise spheres with shape deviations of less than 20 nm at a diameter of about 94 mm and with a defect-free polished surface were prepared from the 28Si crystals grown at IKZ using the float-zone method (FZ). Under these preconditions, PTB succeeded in determining the number of 28Si atoms in a crystal sphere of 1 kilogram total mass, with the required uncertainty of less than 2 x 10-8

It amounts to:      2,152538397 x 1025 atoms of silicon-28   

In order to guarantee the necessary purity of the crystals grown from this material, various material-intensive molten-zone cleaning steps are necessary. The special challenges were therefore the approx. 1000 times higher material price compared to conventional silicon as well as the limited amount of material availability.

Silicon is regarded as a very comprehensively investigated semiconductor material that dominates microelectronics and thus communication technologies worldwide. The IKZ will continue to work on the extreme requirements for the further improvement of material properties in order to enable future applications such as artificial intelligence and quantum technologies. „IKZ´s expertise on isotope pure Si crystals, developed during this metrology project, will allow us to play in the next round a key role as materials science institute for the development of innovative quantum technologies“, states Prof. Dr. Thomas Schröder, Scientific Director at IKZ.

Si kg

 More information can be found at


"28-02-2019: G-ray Nanotech and the Leibniz-Institut für Kristallzüchtung (IKZ) join forces to
develop detector-grade Gallium Arsenide wafers"

GAs 01Gallium arsenide single crystal 4", grown with the VGF method | Photo: IKZ

New platform for very high performance X-ray detectors:
G-ray Nanotech and IKZ have entered into a research and development collaboration covering the doping of Gallium Arsenide structures and the manufacturing of high purity crystals in wafer form factor for detector applications.

We are delighted to work with a world-leading institute in the field of material sciences, says Philippe Le Corre, CEO of G-ray Nanotech. The competencies of IKZ will allow us to accelerate significantly the expansion of our latenium™ detector architecture into medium-large energy X-rays applications as well as in the infra-red spectrum.

G-ray Industries SA, a Neuchâtel start-up, is currently developing ultra-high performance detectors dedicated to industrial non-destructive testing solutions. These ultra-high-performance detectors are developed in partnership with CSEM, based on G-ray’s revolutionary patented latenium™ technology.

The latenium™ Evaluation kits are available for evaluation purposes as of Q1-2019. In addition, the G-ray technologies - in particular the covalent bonding of a silicon wafer to a GaAs, Ge or Si wafer at low temperatures and the very fast epitaxial growth of Germanium structures - are being positioned in the fields of high-energy physics research for new particle detectors and in vision systems for the automotive industry.

We are pleased to start a long-term collaboration with G-ray Industries, says Prof. Thomas Schroeder, IKZ´s Scientific Director: IKZ is committed to push high performance crystalline materials to market applications and the state-of-the-art X-ray imaging detector development at G-Ray is a nice opportunity for us. We consider 3D heterointegration via bonding approaches as a fruitful strategy for us to innovate technologies by high quality, precisely tailored crystalline materials.

“With our expertise in materials science and technology we have supported the G-ray team right from the start. This is an outstanding opportunity to bring a ground-breaking X-ray detector technology to the market”, says Gian-Luca Bona, CEO of Empa, the Swiss Federal Laboratories for Material Science and Technology.

Additionnal information :
G-ray Nanotech SA


October 11th, 2018: Family-friendly employer: Leibniz-Institut für Kristallzüchtung receives again the certificate for the audit berufundfamilie (work and family audit)

On September 30, 2018, the Leibniz-Institut für Kristallzüchtung (IKZ) was awarded the berufundfamilie audit certificate for further three years. The certificate is awarded to the institute for its commitment in the area of strategically oriented family and life-phase conscious personnel policy.

Logo audit beruf familie A4

The prerequisite for certification is the successful completion of the auditing process offered by berufundfamilie Service GmbH, which initiates and pursues a systematic process of operational compatibility. In the auditing process, the existing instruments to support the compatibility of work, family and private life were evaluated and further company-specific measures agreed.
The renewed certification shows that the IKZ is continuously working on a family-friendly personnel policy. The Institute is dedicated to improve the framework conditions for its employees and to provide them with instruments with which family/private life and career can be better reconciled. This includes, for example, flexible options for the organisation of working time, whether it be daily working time or (temporary) part-time employment. A parent-child room is available to employees to bridge short-term bottlenecks in child care.


31.01.2018: Thomas Schröder appointed as new director of the Leibniz Institute for Crystal Growth  

On February 1st, 2018 Prof. Dr. Thomas Schröder becomes head of the Leibniz Institute for Crystal Growth (IKZ) in Berlin-Adlershof, Germany. Associated with the position of director is the professorship "Crystal Growth" at the Humboldt University of Berlin. Since 2013, Prof. Dr. Günther Tränkle, director of the Ferdinand-Braun-Institutes für Höchstfrequenztechnik, has been acting as temporary director of the institute, which has enabled the IKZ to develop into a leading centre for crystal growth in Europe and worldwide

Thomas Schröder has held a professorship for semiconductor materials at the Brandenburg University of Technology (BTU) Cottbus-Senftenberg since 2012 and has been head of the Materials Research Department at the IHP GmbH - Innovations for High Performance Microelectronics (IHP) in Frankfurt (Oder) since 2009. With his team he conducts modern materials research in the field of "More than Moore" silicon microelectronics. As a chemist and physicist Thomas Schröder received his PhD in the area of physical chemistry of dielectrics at Humboldt University Berlin after a research study at the Fritz Haber Institute of the Max Planck Society in Berlin.

The Leibniz Institute for Crystal Growth researches the scientific and technological challenges of crystal growth. This ranges from basic research to industry-oriented technology development. The materials developed at the institute form the basis for modern technical applications that are used in microelectronics, opto- and power electronics, photovoltaics, optics, laser technology and sensor technology. In addition, the institute fulfils a supraregional service function that includes the provision of special crystals for research, the characterization of crystalline materials or the development of technologies for research and industry.


January 22nd, 2018: Researchers reveal the fundamental limitation in the key material for solid-state lighting

For the first time an international research group has revealed the core mechanism that limits the indium (In) content in indium gallium nitride ((In, Ga)N) thin films – the key material for blue light emitting diodes (LED). Increasing the In content in InGaN quantum wells is the common approach to shift the emission of III-Nitride based LEDs towards the green and, in particular, red part of the optical spectrum, necessary for the modern RGB devices. The new findings answer the long-standing research question: why does this classical approach fail, when we try to obtain efficient InGaN-based green and red LEDs?

Despite the progress in the field of green LEDs and lasers, the researchers could not overcome the limit of 30% of indium content in the films. The reason for that was unclear up to now: is it a problem of finding the right growth conditions or rather a fundamental effect that cannot be overcome? Now, an international team from Germany, Poland and China has shed new light on this question and revealed the mechanism responsible for that limitation.

In their work the scientists tried to push the indium content to the limit by growing single atomic layers of InN on GaN. However, independent on growth conditions, indium concentrations have never exceeded 25% - 30% – a clear sign of a fundamentally limiting mechanism. The researchers used advanced characterization methods, such as atomic resolution transmission electron microscope (TEM) and in-situ reflection high-energy electron diffraction (RHEED), and discovered that, as soon as the indium content reaches around 25 %, the atoms within the (In, Ga)N monolayer arrange in a regular pattern – single atomic column of In alternates with two atomic columns of Ga atoms. Comprehensive theoretical calculations revealed that the atomic ordering is induced by a particular surface reconstruction: indium atoms are bonded with four neighboring atoms, instead of expected three. This creates stronger bonds between indium and nitrogen atoms, which, on one hand, allows to use higher temperatures during the growth and provides material with better quality. On the other hand, the ordering sets the limit of the In content of 25%, which cannot be overcome under realistic growth conditions.

“Apparently, a technological bottleneck hampers all the attempts to shift the emission from the green towards the yellow and the red regions of the spectra. Therefore, new original pathways are urgently required to overcome these fundamental limitations”, – states Dr. Tobias Schulz, Leibniz Institute for Crystal Growth, Berlin, Germany, “For example, growth of InGaN films on high quality InGaN pseudo-substrates that would reduce the strain in the growing layer.”

However, the discovery of ordering may help to overcome well known limitations of the InGaN material system: localization of charge carriers due to fluctuations in the chemical composition of the alloy. Growing stable ordered (In, Ga)N alloys with the fixed composition at high temperatures could thus improve the optical properties of devices.

The work is a result of a collaboration between Leibniz-Institut für Kristallzüchtung (Berlin, Germany), Max-Planck-Institut für Eisenforschung (Düsseldorf, Germany), Paul-Drude Institut für Festkörperelektronik (Berlin, Germany), Institute of High-Pressure Physics (Warsaw, Poland), and State Key Laboratory of Artificial Microstructure and Mesoscopic Physics (Beijing, China).

The article is published in:

January 31st, 2018: Thomas Schröder appointed as new director of the Leibniz Institute for Crystal Growth

On February 1st, 2018 Prof. Dr. Thomas Schröder becomes head of the Leibniz Institute for Crystal Growth (IKZ) in Berlin-Adlershof, Germany. Associated with the position of director is the professorship "Crystal Growth" at the Humboldt University of Berlin. Since 2013, Prof. Dr. Günther Tränkle, director of the Ferdinand-Braun-Institutes für Höchstfrequenztechnik, has been acting as temporary director of the institute, which has enabled the IKZ to develop into a leading centre for crystal growth in Europe and worldwide



March 27th, 2017: Berliner Start-up GOLARES erhält Leibniz-Gründerpreis 2017

Sorry, this article is not available in english language!

Die Berliner Ausgründung GOLARES vom Leibniz-Institut für Kristallzüchtung (IKZ) in Adlershof erhält den Gründerpreis der Leibniz-Gemeinschaft 2017. Die Auszeichnung ist mit einem Preisgeld von 50.000 Euro dotiert, das für die weitere Entwicklung des Unternehmenskonzepts eingesetzt werden kann.

GOLARES hat ein Verfahren zum hochpräzisen und homogenen Beschichten sowie zum effizienten Strukturieren von Bauelementen entwickelt, die zum Beispiel in Lasern oder Sensoren vieler Hightech-Produkte zum Einsatz kommen. Mit einer neuentwickelten Plasmaquelle ist GOLARS in der Lage, dünne Schichten aus Titan- und Aluminiumnitrid herzustellen, die sich durch besondere Härte, Wärmeleitfähigkeit und chemische Beständigkeit auszeichnen. Die so produzierten Wafer bilden die Grundlage für Mikrochips, die in verschiedenen elektronischen und opto-elektronischen Bauelementen verwendet werden.

GOLARES zielt besonders auf innovative kleine und mittelständische Unternehmen, die Plasma-Prozessierung für Kleinserien, Vorversuche und Prototypen, aber auch entsprechende Infrastrukturen nicht selbst vorhalten können. Die dafür eingesetzte Technik verspricht ihnen robustere Produkte mit einer höheren Lebensdauer.

Hinter GOLARES stehen mit Sebastian Golka, einem promovierten Elektroingenieur, und Michael Arens, einem promovierten Physiker, zwei Spezialisten für Plasmaprozesstechnik. Michael Arens bringt dazu Erfahrungen in Vertrieb und Betriebswirtschaft mit.

GOLARES wurde zuletzt mit einem EXIT-Gründerstipendium des Bundeswirtschaftsministeriums für Existenzgründungen aus der Wissenschaft gefördert und vom Gründungsservice Leibniz-Transfer der Leibniz-Gemeinschaft unterstützt. Seit Juni 2016 hat GOLARES als GmbH den operativen Betrieb aufgenommen.

Für den Leibniz-Gründerpreis 2017 waren neben GOLARES drei weitere, hervorragende Gründungsprojekte aus Leibniz-Instituten nominiert, darunter auch MSim – Microelectronic Simulations vom Weierstraß-Institut für Angewandte Analysis und Stochastik in Berlin (WIAS), das moderne und hochwertige Simulations-Produkte für Hersteller von Halbleiter-Bauelementen anbietet. IKZ und WIAS gehören zum Forschungsverbund Berlin e.V., der in diesem Jahr sein 25-jähriges Bestehen feiert.

Mit dem Gründerpreis der Leibniz-Gemeinschaft werden Ausgründungsvorhaben aus Leibniz-Instituten in der Vorbereitungs- bzw. Start-up-Phase unterstützt. Das Preisgeld ist zweckgebunden für Beratungsleistungen bei der Überprüfung und praktischen Umsetzung der Unternehmenskonzepte. Dabei geht es insbesondere um Herausforderungen wie Markteintritt, Einwerbung einer Finanzierung oder Entwicklung von Marketing- und Vertriebskonzepten. Die Begutachtung der eingereichten Vorschläge erfolgte durch die Preis-Jury der Leibniz-Gemeinschaft, die sich aus leitenden Wissenschaftlern von Leibniz-Instituten und Personen des öffentlichen Lebens zusammensetzt, darunter ausgewiesene Experten für Ausgründungen und Wissenstransfer.

Weitere Informationen zum Leibniz-Gründerpreis unter:

Partnerlogo 1 EN

Partnerlogo 2

Partnerlogo 3