SIZE EFFECT IN THE THERMAL EMF OF MULTIVALLEY SEMICONDUCTORS

A size effect involving the intervalley distance L(upsilon) and the co oling length L(epsilon) in the thermal emf of multivalley semiconducto rs of the n-Si type is examined theoretically. The method used involve s seeking solutions for the symmetric part of the distribution functio n f0(alpha) (epsilon, r, t) in the valleys as an expansion in eigenfun ctions of an operator responsible for the quasielastic intervalley sca ttering. In thin samples, the thermal emf becomes anisotropic and may be several times the thermal emf of a bulk sample.