THz Spectroscopic Electron Paramagnetic Resonance of the Fe3+ Defect in GaN

We present a recently developed method for electron paramagnetic resonance (EPR) measurements in the THz spectral range. The method is based on spectroscopic ellipsometry and thus requires no cavity, unlike conventional EPR. This permits us to scan the frequency parameters in addition to the magnetic field parameters. To showcase this, both frequency and magnetic field scans are performed on Fe-doped GaN, and the results are compared to previous work that used conventional EPR to study the same defect.