Ultra-low field frequency-swept electrically detected magnetic resonance

We have developed a new ultra-low field frequency-swept (FS) electrically detected magnetic resonance (EDMR) spectrometer to perform sensitive EDMR measurements of 4H-silicon carbide (SiC) metal–oxide–semiconductor field-effect transistors at sub-millitesla (mT) fields. The design enables the detection so-called ultra-strong coupling effects such as multiple-photon transitions and Bloch–Siegert shifts. In this paper, we present discuss FS-EDMR sensitivity both multiphoton shifts response. effectively eliminates interference sub-mT response from near-zero magnetoresistance (NZFMR) phenomenon that pervades regime in field-swept scheme. an automatic power leveling scheme, which frequency sweeping. also results illustrating shift Finally, study two-photon transition line shape 4H-SiC transistor function static field, observe collapse linewidth with decreasing compare our theory absorption EDMR.