Semiconductor Quantum Materials

The group explores innovative integration concepts of elementary group IV semiconductor materials (carbon, silicon, germanium, tin and their alloys) for the silicon technology platform.  Their inherent material properties can be leveraged to improve device performance and add functionalities based on quantum effects for applications in optoelectronics and quantum computing.

To achieve the in-depth knowledge required to fully control the properties of these material systems and their possible integration, our group exploits synergistic competencies in innovative device development, state-of-the-art characterization techniques in combination with theoretical modeling.

Research relevance and application areas

Low-dimensional Group IV quantum materials such as 2D quantum well, 1D quantum wires or 0D quantum dots hold considerable potential for quantum computing, scalable nanoelectronics, photonics, and quantum sensing.

Si and Ge quantum wells are the most promising platform for CMOS-compatible quantum bit (qubit) devices which may enable highly scalable quantum processing units and eventually quantum advantage for innovative applications in cryptography, data processing and quantum simulations.

Alloys incorporating Sn are in particular attractive for optoelectronic devices operating in the infrared to Terahertz range. Key applications include optical interconnected communication, environmental monitoring and LiDAR systems.  

Main research objectives:

• Develop integration processes and innovative devices in close collaboration with the Technology department for quantum computing and optoelectronics.
• Group IV heterostructure epitaxy using CVD in a CMOS-compatible cleanroom environment and MBE for explorative research.
• Materials investigation using a comprehensive set of state-of-the-art techniques to determine inherent structural properties and correlate them with application-oriented optical as well as electrical characterization.
• Apply and promote cutting-edge synchrotron radiation-based techniques for a rigorous in-depth materials characterization.

Research areas

The working group Semiconductor Quantum Materials from the Materials Research department develops semiconductor-based qubits in SiGe heterostructures in a combined effort with the Technology department. In addition, the Jülich Research Center, RWTH Aachen University and the IHP are combining their complementary expertise in the field of semiconductor and quantum technology. We work together in an open-ended cooperation, as part of a joint lab, on the development of scalable qubits that make quantum computers possible on a semiconductor platform. The IHP contributes its expertise in the growth and characterization of heterostructures and fabrication of Ge/SiGe and Si/SiGe qubit components. In addition, the Forschungszentrum Jülich and RWTH Aachen have demonstrated expertise in the field of device conceptualization, fabrication, characterization and operation as part of the joint JARA Institute for Quantum Information.

Furthermore, the innovative quaternary material system CSiGeSn, which has great potential for future Group IV semiconductor optoelectronics, is intensively researched. The flexible semiconductor alloy makes it possible to precisely vary the addressable wavelength by adjusting the Sn concentration and the strain. The growth of CSiGeSn layer systems of appropriate quality on silicon is a major challenge. Thus, we want to develop molecular beam epitaxy processes further for exploratory sample manufacturing.

In the laboratories of the Materials Research department, the structural, chemical and optical properties of strained CSiGeSn are investigated in a multiscale approach (from the atomic to the micrometer scale). In addition, also in close collaboration with the Jülich Research Center, which produces “proof-of-concept” components based on the findings gained, we investigate the structural and optical materials properties at the bases of GeSn-based optically- and electrically- pumped lasers, photodetector, and on chip thermoelectric devices.

Projects