Study of Thermoelectric Properties of Bi-doped ZnTe Thin Films Using Thermal Evaporation
| Autor: | Wen-Hua Kao, 高文華 |
|---|---|
| Rok vydání: | 2014 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 102 In this study, we report the effects of the various parameters such as Zn:Te ratio, annealing temperature (200~400oC), and Bi additions (10~40wt%) on the properties of ZnTe/Bi-doped ZnTe thin films are investigated and discussed. The physical and chemical characteristics of the thin films were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscope (AFM), and electron spectroscopy for chemical analysis (ESCA). Furthermore, the thermoelectric properties of ZnTe thin film were also measured by hall system and self-made fixture. According to the results of physical analysis, the films were more dense and uniform with at an optimum parameter such as an annealing temperature of 300oC, a Zn:Te ratios of 1:1. In addition, there have not any secondary phases, and the thermoelectric figure of merit of ZnTe film is about 2.21×10-5 in this conditions. On the other hand, it is found that the optimum of Seebeck coefficient and electrical resistivity at 20wt% Bi-doped ZnTe thin film because the resistivity was decreased and the thermoelectric figure of merit was increased to 0.141 at room temperature. Finally, a thermoelectric device is composed of p-type 20wt% Bi-doped ZnTe thin film and n-type 40wt% Bi-doped ZnTe thin film that are connected in series, forming a PN structure. The measured output voltage of the device is 1.56 μV. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|