Solid state spectroscopy / semiconductor diagnostics
The future development of microelectronics requires a detailed understanding of the materials used. For most applications, silicon is the material of choice, but also GaAs is widely used. However, for certain classes of electronic devices, Si and GaAs cannot be employed due to their fundamental physical properties. One example is light-emitting devices in the visible and ultraviolet spectral region. For such applications, other materials have proven to outperform Si and GaAs. However, many properties of such new electronic materials (like GaN, SiC, Cu(In,Ga)Se2, but also organic semiconductors) are still poorly understood. Further improvement of devices based on these semiconductors requires further research concerning, e.g., the defect chemistry.
Our activities can roughly be divided into three areas:
- Understanding and visualization of technologically relevant defects (point defects as well as extended defects), in particular by means of topographical methods;
- Structural identification of point defects and detailed investigations of their electrical and optical properties (both in classical semiconductors and in new materials);
- Refinement of existing and development of new experimental techniques for solid-state spectroscopy and semiconductor diagnostics.
Even though the focus of our work is on semiconducting materials, many of our spectroscopic methods can be (and are) applied to other classes of materials as well. Concerning spin resonance techniques like ESR, we have had projects in organic and anorganic chemistry, biology, but also mineralogy.