Terahertz Electron Paramagnetic Resonance Ellipsometry for defect characterization of ultrawide bandgap semiconductors

The purpose of this project is to develop unique terahertz electron paramagnetic resonance ellipsometry (THz-EPR-E) and explore it to advance research in ultra-wide band gap (UWBG) semiconductors for next generation green power electronics.

This new approach enables frequency scanning EPR, as well as substantial improvement in energy resolution and in sensitivity to spin volume densities.

The specific goals include:Develop THz-EPR-E and respective magnetic permeability tensor modelling approaches.Use THz-EPR-E to characterize defect related spin signatures in UWBG β-Ga2O3 and related Al alloy bulk and epitaxial structures as a function of doping (donors and acceptors), purity (impurity and point defects), composition and strain.The project will make use of the only THz ellipsometer in Europe developed in my group for the proposed elaboration of THz-EPR-E.

The new THz-EPR-E will allow to explore for the first time the polarization, directional and chiral properties of a spin transition and the possibility to identify the spatial location of the spins within heterostructures.

Expected impact is to produce significant progress in understanding and control of defects in UWBG semiconductors needed for enabling efficient power switching and conversion for sustainable energy system. The THz-EPR-E is a new method with the potential to benefit the broader community of materials science.