Transport properties and lattice variation behavior as a function of temperature in Sb2Te3 nanorod array

- A uniquely Sb2Te3 nanorod array was fabricated by a magnetron sputtering method.
- The unit cell volume v and the lattice parameters a and c are a function of temperature.
- The unit cell volume and lattice parameters affect the transport properties of materials.
- The anomalous thermal expansion behavior appears in the nanorod array.

In this paper, it was found that unit cell volume and lattice parameters can importantly influence transport properties of Sb2Te3 nanorod array. Here the p-Sb2Te3 nanorod array has been successfully fabricated by the simple magnetron co-sputtering method. The structure and thermoelectric transport properties of Sb2Te3 nanorod array are investigated by means of X-ray diffraction and thermoelectric measurements. The results show that the unit cell volume v and the lattice parameters a and c of Sb2Te3 nanorod array is a function of temperature. The thermal expansion coefficients along the (0 1 5) and (1 0 10) crystal faces are different in Sb2Te3 nanorod array. There exist the highest values of v, a and c at 250 °C. The anomalous thermal expansion behavior appears in the temperature range 250-300 °C. The unit cell volume and the lattice parameters affect the values of electrical conductivity (σ) and Seebeck coefficient (S), and hence could be considered as one of origins of the experimental observations. For the volume maximum expansion by 0.62% in Sb2Te3 nanorod array, a concomitant maximum increase in σ and S by 1.9 × 104 S/m and 43 μV/K are achieved, respectively, in the temperature range of 25-300 °C. This method will prove to be a promising way to obtain further insight into the relation between temperature and transport properties.