The group explores innovative integration concepts of elementary group IV semiconductor materials (carbon, silicon, germanium, tin and their alloys) into 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 precisely control the properties of these material systems and their possible integration, our group exploits synergistic competencies in advanced, state-of-the-art experimental techniques at the nanoscale and theoretical modeling.
Main targets
- 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 more 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.
- Computational modelling (FEM simulations using COMSOL & Lumerical, tight-binding & effective mass theory) of mechanical, optical, electromagnetic and electrical properties.
- Apply and promote cutting-edge synchrotron radiation based techniques for a rigorous in depth materials characterization.
Research topics
The working group Semiconductor Optoelectronics from the Materials Research department develops semiconductor-based quantum bits (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 in qubit fabrication based on Ge/SiGe and Si/SiGe compounds. In addition, the Forschungszentrum Jülich and RWTH Aachen have proven expertise in the field of device conception, characterization and qubit demonstration 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. 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 explorative 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 material properties of GeSn-based optically- and electrically- pumped lasers, photodetectors, and on chip thermoelectric devices.
Within the International Joint Lab established together the University of Roma Tre, we also carry our research in the field of Ge/Si based quantum cascade structures for application in the field of THz optoelectronics. In particular, our team support the research efforts by thoroughly characterizing the complex heterostructures deposited at Roma Tre by state-of-the-art ultra-high vacuum CVD.
Controlling strain and segregation properties to produce complex heterostructures for further performance enhancement of the material plays a central role in this working group. Therefore, long-standing collaborations are established, particularly with the European Synchrotron Radiation Facility (ESRF). Cutting-edge nano-focused X-ray diffraction and atomistic spectroscopy experiments are carried out here in order to analyze, simulate and refine these structural properties.
