ヘマタイトの熱電変換特性に及ぼす陽極酸化条件の影響

Abstract

The purpose of this study is to investigate the effect of fabrication conditions for α-Fe2O3 based thermoelectric conversion elements. It was demonstrated that the open circuit voltage of α-Fe2O3 thermoelectric conversion elements could be enhanced by decreasing the load current density used in production of the film by anodic oxidation. α-Fe2O3 films were fabricated under various oxidizing condition in an aqueous solution of FeCl3, KF, KCl and H2O2 at the temperature of 50 °C. The load current density and oxidation time were varied. The amount of α-Fe2O3 in the α-Fe2O3 film, the crystal quality and the crystal grain size of the α-Fe2O3, were evaluated. In terms of the maximum value of the open circuit voltage, the best film thickness of the α-Fe2O3 film was found to be about 40 ~ 50 μm. α-Fe2O3 films with greater crystal quality and larger crystal grain size can be fabricated by decreasing the load current density. These improvement on α-Fe2O3 thermoelectric conversion elements lead to more powerful thermoelectric conversion element, i.e., higher open circuit voltage.