A search for trends in the thermopower of GaAs-Ga1-xAlxAs heterojunctions

Abstract
The authors report the results of two types of experiments on the thermo-electric coefficients of GaAs-Ga1-xAlxAs heterojunctions. In the first set of experiments, the density and mobility of a two-dimensional electron gas has been varied over a wide range by illumination. The zero-field thermopower is reduced by the increased carrier density but the oscillation amplitude at any particular field is insensitive to it. In the second set of experiments they have increased the phonon mean free path in the GaAs substrate by polishing the rear surface. This results in an increase in magnitude of the thermo-electric coefficients which is consistent with phonon drag effects.