Lawrence Berkeley National Laboratory

We have measured the electrically detected magnetic resonance of donor-doped silicon field-effect transistors in resonant X- (9.7GHz) and W-band (94GHz) microwave cavities. The two-dimensional electron gas (2DEG) resonance signal increases by two orders of magnitude from X- to W-band, while the donor resonance signals are enhanced by over one order of magnitude. Bolometric effects and spin-dependent scattering are inconsistent with the observations. We propose that polarization transfer from the donor to the 2DEG is the main mechanism giving rise to the spin resonance signals.