INFLUENCE OF OXYGEN IMPURITY ON SEEBECK COEFFICIENT OF NANOSCALE MnSi1.7 FILMS

Abstract

Nano-scale MnSi 1.7 films are prepared by thermal annealing of three-layer Si / MnSi x/ Si or bi-layer Si / MnSi x (x < 1.7) structures at 923 K for 20–65 minutes. These layers are deposited on thermally oxidized silicon substrates at about 393 K by electron beam evaporation. It is found that the oxygen content in the MnSi 1.7 film can be reduced from about 10 at.% to 6 at.% by using the bi-layer structure MnSi x/ Si with the MnSi x layer on top. With the reduction of oxygen content in the MnSi 1.7 film, the transition temperature from p-type to n-type decreases from 508 K to 463 K or less.