논문 해외 국제전문학술지(SCI급) METHOD OF EFFICIENT AG DOPING FOR FERMI LEVEL TUNING OF THERMOELECTRIC BI0.5SB1.5TE3 ALLOYS USING A CHEMICAL DISPLACEMENT REACTION
- 학술지 구분 국제전문학술지(SCI급)
- 게재년월 2015-08
- 저자명 오민욱
- 학술지명 JOURNAL OF PHYSICAL CHEMISTRY C
- 발행처명 AMER CHEMICAL SOC
- 발행국가 해외
- 논문언어 외국어
- 전체저자수 5
홈페이지논문 초록 (Abstract)
Silver is a well-known element for use as a p-type dopant in Bi2Te3-related compounds. In this paper, an efficient method for incorporating ultralow Ag dopant concentrations (<1300 ppm) into Bi0.5Sb1.5Te3 via a simple chemical displacement react ion is described. Powders of Bi0.5Sb1.5Te3 synthesized by mechanical all oying were reacted with Ag ions in dilute HNO3 solutions (pH 0.2) , resulting in the deposition of Ag on the surface of the powders due to the difference in reduction potential between Ag and Bi0.5 Sb1.5Te3. The Ag/Bi0.5Sb1.5Te3 powders were then sintered by spark p lasma sintering (SPS), and the thermoelectric properties of the dense Ag-doped samples were measured. Low Ag-doped samples showed behaviorc haracteristic of partially degenerate semiconductors, while highly dop ed specimens exhibited properties associated with fully degenerate semiconductors. From the measured transport properties and theoretica l estimations, successful tuning of the Fermi level with Ag was conf irmed. Consequently, the temperature at which the peak dimen sionless figure of merit (ZT) value was obtained increased from SO to 25 0 degrees C. Such findings may be beneficial in the utilization of wast e heatover a wide temperature range, as the Ag-doped samples could be e mployed as functionally graded materials for thermoelectric modu les.