X-band room temperature spectra obtained by rapid-scan, continuous wave, field-swept echo-detected and Fourier transform electron paramagnetic resonance (FTEPR) were compared for three samples with long electron spin relaxation times: amorphous hydrogenated silicon (T1 = 11 s, T2 = 3.3 s), 0.2% N@C60 solid (T1 = 120-160 s, T2 = 2.8 s) and neutral single substitutional nitrogen centres (NS) in diamonds (T1 = 2300 s, T2 = 230 s). For each technique, experimental parameters were selected to give less than 2% broadening of the lineshape. For the same data acquisition times, the signal-to-noise for the rapid-scan spectra was one-to-two orders of magnitude better than for continuous wave or field-swept echo-detected spectra. For amorphous hydrogenated silicon, T2 (∼ 10 ns) is too short to perform FTEPR. For 0.2% N@C 60, the signal-to-noise ratio for rapid scan is about five times better than for FTEPR. For NS the signal-to-noise ratio is similar for rapid scan and FTEPR.
- hydrogenated silicon
- rapid-scan EPR
- single substitutional N in diamond