Thermoelectric and hot-electron properties of a silicon inversion layer

Electron-phonon coupling of a two-dimensional electron gas in a Si metal-oxide-semiconductor field-effect transistor in the temperature range 0.3 K < T < 4 K has been investigated using phonon-drag thermopower S-g and electron energy loss rate F(T). At low temperatures (the Bloch limit) we find S-g proportional to T-6, as expected for electron-phonon scattering mediated by a screened deformation potential, and the magnitude is in excellent agreement with a calculation using no adjustable parameters; the calculation continues to give good agreement at higher temperatures. F(T) has been calculated using the same input parameters as for S-g. Reasonably good agreement is found with the observed values for T>1.5 K, but at lower temperatures the measured F(T) is much larger than predicted and also exhibits a much weaker temperature dependence. Possible reasons are suggested.