Neutral donors interacting with a two-dimensional electron gas measured by electrically detected magnetic resonance up to 94GHz

Electrically detected magnetic resonance of a silicon field-effect transistor with channel-implanted donors is measured in a W-band ($94\:$GHz, $3.36\:$T) resonant microwave cavity. It is found that the two-dimensional electron gas (2DEG) resonance signal intensity increases by two orders of magnitude compared with conventional low-field X-band ($9.7\:$GHz, $0.35\:$T) measurements. On the other hand, the neutral donor resonance signals increase by over one order of magnitude. We interpret the results in terms of direct spin-dependent scattering and a polarization transfer from the donors to the 2DEG spin system.