Tailoring orientation of microstructure for improving thermopower factor in Mg-doped CuCrO2 thick films

Abstract

This study changed the material thickness (0.5-2.7 μm) to control the orientation of microstructure for tailoring the thermopower factor of CuCr0.85Mg0.15O2 films. As a result, the (110)-preferred orientation and copper vacancies were dominant in the thicker film, which increased conductivity σ. The Seebeck coefficient S remained unchanged within the wide film thickness range despite the remarkable increment in σ. Therefore, the thermopower factor (PF = S2σ) of the CuCr0.85Mg0.15O2 films drastically increased with the increase in the film's thickness, reaching 720 μW/mK2 at 500 °C in a 2.0 μm-thick CuCr0.85Mg0.15O2 film. This value is better than that observed in the bulk materials. A detailed discussion of physical mechanisms is presented in this manuscript.