Silver fragments of the semiconductor material germanium and the image of the element with the letters GE from the periodic table.

Purest germanium might pave the way for quantum computations and communications

IKZ joins hands with HU and DLR to reveal new physical properties at the quantum limit and to develop a technological base for new generation single-electron devices

Germanium (Ge) has been demonstrated as the purest material that human beings could prepare among all semiconductor materials. Ultra-high purity germanium (u-HPGe) crystalline material with a net charge carrier concentration well below the intrinsic level (<≈1010 cm-3 at low temperatures) has greatly stimulated interest both in basic physics and novel applications of Ge in recent years. Until now doped semiconductors are primarily used for electric-field driven high-density electron devices while single-electron semiconducting transistors consider commonly nanometer-size structures, such as doped quantum dots. On the other hand, particularly high-purity combined with tailored very low-level doping and co-doping is very promising to investigate the physical properties of such a unique single crystalline material up to a single-electron limit of a dopant. At a very low dopant concentration in a bulk semiconductor, its interaction with neighboring impurities vanish to a real single-electron physical limit, for which properties are not yet explored due to lack of such a customized material. Probing the attractive primary properties of crystals co-doped with acceptors of different valences slightly above their residual level is also of fundamental interest.

This exciting research is funded by the DFG and will be carried out in close collaboration with Humboldt-University (HU)/ German Aerospace Center (DLR)-Institute of Optical Sensor Systems, Berlin. The research also includes crystals with selected isotopic content by enrichment or depletion of lattice and impurity atoms, as till to date the properties of isotopically enriched Ge crystals are not known completely and are investigated very scarcely. The goal is getting new insights on interaction of charge carriers bound to impurity centers with a host lattice (electron-phonon interactions), interaction with local vibrational modes, as well as with different isotopes, both on the host lattice and on the impurity sites. In this very challenging project, IKZ-Berlin will intend to prepare and do processing of such materials for researching the underlying properties of this new, not yet available material while HU/DLR will characterize the optical properties of the novel material. All these planed works are envisaged to shed some lights into unknown properties of this class of crystals.

German Aerospace Center (DLR) Institute of Optical Sensor Systems, Berlin

The Institute of Optical Sensor Systems defines the development of geometrically and/or spectrally high-resolution sensor systems in the visible and infrared range of electromagnetic radiation as well as the thematic real-time processing of image data into user-relevant information as strategic goals. The operational use of such sensors requires an extensive autonomy, which includes an independent operation of the system. To this end, the facility is involved in the development of small satellites.

Of crucial importance for the work of the facility is the pursuit of systemic approaches that take into account all optical, mechanical, electronic and information technology aspects in the development of a sensor system. The structure of the OS facility takes this into account.

Leibniz Institute for Crystal Growth (IKZ), Berlin

The Leibniz Institute for Crystal Growth (IKZ) in Berlin-Adlershof is an international competence center for science & technology and service & transfer in the field of crystalline materials. The R&D spectrum ranges from basic and applied research topics to pre-industrial research tasks.Crystalline materials are key technological components for the realization of electronic and photonic solutions for societal challenges. These include artificial intelligence (communication, sensor technology, etc.), energy (renewable energies, energy conversion, etc.) and health (medical diagnostics, modern surgical operation systems, etc.).

The IKZ develops innovations in crystalline materials through a combined in-house expertise consisting of equipment engineering, numerical simulation and crystal growth to achieve crystalline materials of the highest quality and with tailored properties. Research on bulk crystals represents the unique selling point of the house. This work is accompanied by R&D on nanostructures and thin films. A strong theoretical and experimental materials research is another asset of the IKZ.

Together with partners from institutes with affiliated technology platforms as well as industrial companies, the institute will also increasingly drive innovations through crystalline materials in the future. These include the reliable evaluation and assessment of innovative crystalline prototype materials for disruptive technology approaches.


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Source: Press release IKZ Berlin“Purest germanium might pave the way for quantum -computations and -communications”, Jan 16th, 2023; photonics cluster Berlin Brandenburg; Febr 24th, 2023