Low-temperature electron-phonon interaction in Si MOSFETs

We investigate electron-phonon coupling in a silicon metal-oxide-semiconductor field-effect transistor by measuring heat flow. Earlier studies of the electron-phonon interaction through similar measurements were complicated by electron diffusion, a competing cooling mechanism. We reduce the diffusion by using an unusually long sample, and account for the remainder by comparing results from two segments of different length. We find that the power dissipation from electron-phonon scattering is proportional to T-5, with a magnitude smaller than theoretically predicted.