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Detailed Program
Paper Number : TE-O01
Time Frame : 11:35~11:47
Presentation Date : Thurse day, 27, November
Session Name : Thermoelectrics
Session Chair 1# : Soonil Lee
Session Chair 2# : Yoshiaki Kinemuchi
Thermoelectric Properties of Titanium Doped Zinc Oxide Thin Films
Venkatraju.JELLA
Chungnam National University
Thermoelectric energy harvesting is the transformation of waste heat into useful electricity for applications — acquired the great interest for energy sustainability. The main obstacle is the low thermoelectric efficiency of materials for converting heat to electricity, quantified by the thermoelectric figure of merit, ZT. The best available n-type materials for use in mid-temperature (500–900K) thermoelectric generators have a relatively low ZT of 1 or less, and so there is much interest in finding avenues for increasing this figure of merit [1]. Among oxides, ZnO has always been attracted much attention because low-cost, nontoxic, stable thermoelectric material but thermoelectric properties of ZnO thin films have not been sufficiently explored, even if they are relatively easy to prepare [2,3]. The main reason is the practical difficulty in the measurement of thermoelectric properties at high temperature.
In this present study, Titanium doped ZnO (TZO) thin films were grown onto SiO2(250 nm)/Si substrate by Co-sputtering method with the using of both Titanium and ZnO targets and annealed at various temperatures ranging from 773 to 1073K in argon ambient for various time. Thermoelectric properties of TZO thin films with various thickness investigated by the different annealing conditions. The Crystalline structure, thickness, morphologies and carrier concentration of the deposited TZO thin films were measured by X-ray diffraction (XRD), Scanning electron microscope (SEM) and Hall measurement respectively. The XRD data indicated that all deposited TZO films have polycrystalline nature, showed only peak at 2¥è ~ 34¡Æ with (002) preferential orientation .This indicating that the films were hexagonal wurtzite structure and showed a good c-axis orientation perpendicular to the substrate. The experimental results showed that the absolute value of Seebeck coefficient of TZO thin film annealed in-between the temperature 873-973K increases stably with increasing of measuring temperature. Also, investigated the dopant different content effect of Titanium in TZO thin films by controlling the deposition powers for better thermoelectric properties.

References:
[1]. Snyder, G. J. & Toberer, E. S. Complex thermoelectric materials. Nature Mater. 7,105–114 (2008).
[2]. J. Mass, P. Bhattacharya, and R.S. Katiyar, Mater. Sci. Eng. B103, 9 (2003).
[3]. B. Singh, Z.A. Khan, I. Khan, and S. Ghosh, Appl. Phys. Lett. 97, 241903 (2010).
Acknowledgements :