The effects of Al-substitution on thermoelectric and charge transport properties of BiCuOSe compounds were investigated. The compounds were prepared by a solid-state reaction and consolidated by SPS (spark plasma sintering). In spite of the increase in the hole concentration with increasing Al amounts in BiCuOSe compound, the electrical conductivity at room temperature was kept constant due to the reduction of mobility. However, electrical conductivities of Al-substituted BiCuOSe compounds at elevated temperature (> 600 K) were higher than those of BiCuOSe, and this result was discussed in terms of it``s the band gap energy. The Seebeck coefficient was drastically reduced when Al was substituted in Bi site, which indicated that the electronic structure was influenced by the Al-substitution into Bi-site.
