“…This method turned out to further improve the thermoelectric figure of merit of the bulk material due to a lowering of the thermal conductivity, while the electrical conductivity and the Seebeck coefficient remained high (Sootsman et al, 2009). This procedure has been applied to ZnO as well, with similar results, namely the reduction of the thermal conductivity by growing a highly disordered polycristalline material, i. e., by introducing interfaces (Alvarez-Quintana et al, 2010;Huang et al, 2011;Igamberdiev et al, 2010). A more defined way of introducing interfaces is to grow multilayers.…”