利用射頻磁控濺鍍法製備P-type Bi0.5Sb1.5Te3 和N-type Bi2Te2.7Se0.3熱電薄膜於PI軟性基板之熱電性質研究

Abstract

Bi2Te3系列化合物為室溫下最佳的熱電性質之材料，依參雜不同的元素可分為P-type Bi0.5Sb1.5Te3 和N-type Bi2Te2.7Se0.3。本實驗利用射頻磁控濺鍍方式製備P-type Bi0.5Sb1.5Te3 和N-type Bi2Te2.7Se0.3熱電薄膜在PI基材上，並改變射頻功率、工作壓力、基材溫度為實驗參數，以得到最佳的熱電特性。並進行XRD、XPS、霍爾效應以及Seebeck效應的量測分析。 P-type Bi0.5Sb1.5Te3方面發現在室溫下，工作壓力為5 mTorr且射頻功率18 W得到之熱電薄膜並於270度下通電流退火5分鐘後可以得到最佳的熱電特性，其Seebeck係數為220.5 μV/K，電阻率則會大幅降低至5 mΩ•cm，熱電功率因子可達到9.59 μW/K2cm。 N-type Bi2Te2.7Se0.3方面發現在基材溫度250度下，工作壓力5 mTorr且射頻功率15W，得到之熱電薄膜並於270度下通電流退火5分鐘後可以得到最佳的熱電特性，其Seebeck係數為177.65 μV/K，電阻率則會大幅降低至3.264x10-2 Ω•cm，熱電功率因子可達到4.158 μW/K2cm。

Bismuth telluride-based compound is currently widely used in thermoelectric material due to its excellent thermoelectric performance around room temperature. By doping different elements, P-type Bi0.5Sb1.5Te3 and N-type Bi2Te2.7Se0.3 can be made. The thermoelectric thin films of Bi0.5Sb1.5Te3 and Bi2Te2.7Se0.3 on polyimide substrates are prepared by radio-frequency (RF) magnetron sputtering. The Bi0.5Sb1.5Te3 and Bi2Te2.7Se0.3 thin films are deposited with different substrate temperature, work pressure and RF power by radio-frequency (RF) magnetron sputtering. Finally, this research analyses the themoeleletric performance, crystal structure and composition by XRD, XPS, Hall effect and the Seebeck effect. This research discovers that the P-type Bi0.5Sb1.5Te3 thermoelectric thin films show the best thermoelectric properties at room temperature with 18 Watts of RF working pressure under 5 mTorrs after electrical annealing treatment at 270 degrees Celsius for 5 minutes；The Seebeck coefficient is 220.5 μV/K, the lowest electrical resistivity is 5 mΩ∙cm, and the highest power factor is 9.59 μW/K2cm. N-type Bi2Te2.7Se0.3 thermoelectric thin films show the best thermoelectric properties at room temperature with 15 Watts of RF, working pressure under 5 mTorrs after electrical annealing treatment at 270 degrees Celsius for 5 minutes and the Seebeck coefficient is 177.65 μV/K,the lowest electrical resistivity is 3.264x10-2 Ω∙cm and the highest power factor is 4.158 μW/K2cm.