Electric and Thermoelectric Properties of ZnO-Based Ceramics Doped with Iron and Cobalt

The relationship between the chemical composition, phase structure, grain size, electrical resistance, and Seebeck coefficient in composite ceramics (ZnO) z [(TM) x O y ] 1 – z (TM = Fe, Co (transition metals); 0 ≤ x ≤ 3, 1 ≤ y ≤ 4, 0.5 ≤ z ≤ 50 wt %), obtained using one- and two-stage technology has been examined. Experimental data on the electrical conductivity, Hall effect, and thermoelectric parameters of doped and undoped ceramics are presented. In the wurtzite phase of the studied ceramics, two levels were found: a shallow level with ionization energy Δ E 1 ≈ 0.04–0.05 eV and a deep level with Δ E 2 ≈ 0.24–0.37 eV. The relationship between the phase composition, electrical conductivity, and thermoelectric power in the studied ceramics has been established. Doping of zinc oxide with iron is shown to be promising for increasing the Seebeck effect.