| 학회 | 한국재료학회 |
| 학술대회 | 2006년 봄 (05/19 ~ 05/20, 경상대학교 ) |
| 권호 | 12권 1호 |
| 발표분야 | 에너지환경재료 |
| 제목 | Control of Carrier Concentration in n-Type Hot-Pressed Bi-Sb-Te Alloys |
| 초록 | Bismuth-telluride-based thermoelectric materials are candidatesfor good thermoelectric materials that operate at near room temperature. Many researchers have made an effort to improve the performance of these materials by optimizing the chemical composition, controlling the carrier concentration, and introducing new preparation methods such as mechanical alloying, doping, hot-pressing, the travelling heater method (THM) and saturation annealing method. It is well known that thermoelectric properties are closely related to chemical composition and carrier concentration, which are affected by the preparation procedures. In this work, we introduce an annealing method performed with only Bi powders at 673K to control the carrier concentration. The hot-pressed alloys and Bi powders are separately placed in the sealed quartz ampoule. Not only are the carrier concentrations controlled, but their conductivity type can also be changed from n-type to p-type by adjusting the annealing time. The annealing time at which the conductivity-type transition occurs is approximately 48 hours. The actual time for the complete transition is expected to depend on the sample size and annealing conditions, such as the annealing temperature and the amount of Bi powders, since the conductivity-type transition is caused by the diffusion of Bi atoms. The thermoelectric properties of the n-type hot-pressed Bi1.8Sb0.2Te3 alloys areinvestigated from the viewpoint of their carrier concentration dependence on the annealing time. This annealing method enables easier control of carrier concentration than the saturation annealing method, which demands accurate control of annealing conditions such as temperature and chemical composition. Furthermore, the method can be applied to hot-pressed alloys, which are employed in the preparation of thermoelectric modules because of their excellent mechanical properties. |
| 저자 | Hee-Joong Im1, Dong-Hwan Kim2, Man-Been Moon3, Hyo-Gyun Kim1, Sung Namkoong1 |
| 소속 | 1HYUNDAI HYSCO, 2Engineering Research Institute, 3Gyeongsang National Univ. |
| 키워드 | figure-of-merit; annealing method; type transition; antisite defects |
