Effect of Cu or Co addition on β-FeSi_2 growth by molten salt method

摘要

β-FeSi_2 bulk crystals were grown by a molten salt method with Cu or Co addition. The effect of the Cu or Co addition on the structural, electrical and thermoelectric properties was investigated. A p-type semiconducting β-FeSi_2 crystal was obtained without any impurity addition. On the other hand, n-type β-FeSi_2 crystals were obtained by Co doping with 1.5-4 mol% addition. For the Cu addition, β-FeSi_2 crystals with large diameter columnar domains were obtained, and an increased p-phase formation was observed. In addition, a slight decrease in the carrier density and a slight increase in the Hall mobility were observed, probably due to the elimination of crystalline defects. The structural and electrical modifications of the β-FeSi_2 crystals by the impurity addition is discussed.