Preparation of Cu3SbSe4 Doping with Aluminum and Studying on its Thermoelectrical Properties

Abstract

The electrical transport and thermoelectric properties of Cu₃Sb_1-xAl_xSe₄ (x = 0, 0.03, 0.05 &0.07) compounds are investigated in the temperature range of (298 – 553) K. The results indicate that with increasing Al content from ( x = 0) to (x =0.07), hole concentration increases monotonically from (2.03×10¹⁸ to 2.82 × 10¹⁸ cm^-3) due to the substitution of Al³⁺ for Sb⁵⁺, thus leading to a large decrease in the electrical resistivity of Cu₃Sb_1-xAl_xSe₄. Meanwhile, the increase in hole concentration leads to a transition from a non-degenerate (x = 0) to a partial degenerate (x = 0.05, 0.07) and then to a degenerate state   (x = 0.07). The power factor (PF) of all the Al-doped Cu₃Sb_1-xAl_xSe₄ samples is remarkably improved due to the optimization of hole concentration. Lattice thermal conductivity k_L of the heavily doped sample(x = 0.07) is reduced. As a result, a large thermoelectric figure of merit ZT = 1.28 is obtained for Cu₃Sb_0.97Al_0.03Se₄ at 458K, which is around 5 times as large as that of the un-doped Cu₃SbSe₄ sample.