本實驗針對Cu2SnSe3-x (-0.04 ≤ x ≤ 0.10)系列樣品於10 K - 350 K溫度區間進行電阻率(ρ)、熱電勢(Ѕ)及熱導率(κ)等熱電傳輸性質之量測。 XRD分析結果顯示晶格常數隨Se缺位增加而上升，至x=0.06後開始下降。整體電阻率隨著Se缺位上升而有下降的趨勢，並在x＝0.08有最低電阻率。電阻率高溫區段藉由小極化跳躍模型(Small polaron hopping)擬合，擬合得知活化能（EA）隨Se缺位量上升而有下降的趨勢。熱電勢於量測溫度區間內皆為正值，顯示主要傳輸載子為電洞，使用"Mott’s formula" 在高溫段進行擬合。Wiedemann-Franz Law計算結果顯示電子熱導率貢獻小於8％，顯示主要熱傳導率由聲子熱導率提供。PF值與ZT值計算結果顯示，硒缺位在x=0.04，於350 K處具有最大值，分別為50 𝜇W / m "K" ^"2" 與0.01。研究結果顯示，調節Cu2SnSe3化合物中硒的比例可有效改善熱電性質。

To improve the thermoelectric performance, we have attempted to tune selenium content in the Cu2SnSe compounds. Electrical resistivity (ρ), thermal conductivity (κ), and Seebeck coefficient (S) measurements were performed on a series of samples Cu2SnSe3-¬x (x = -0.04, 0.00, 0.02, 0.04, 0.06, 0.08, and 0.10) in the temperature range 10 K – 350 K. The powder X-ray diffraction (XRD) patterns for all samples showed a cubic structure. The Rietveld analysis of the powder X-ray diffraction profile indicated that all the samples crystallize in the cubic sphalerite structure (F43 ̅m). The significant enhancement of electrical conductivity in the nonstoichiometric samples leads to the improvement in the power factor, reaching the highest value of ~50 μW/m K-2 at 350 K for Cu2SnSe2.96. The highest ZT value of about 0.01 is achieved at 350 K for Cu2SnSe2.92. The observed results suggest that stoichiometry plays a vital role in tuning the thermoelectric properties in the Cu2SnSe3 compound.

致謝 VII
摘要 IX
目錄 XIII
圖目錄 XV
表目錄 XIX
第一章 前言 1
1.1 簡介 1
1.2 實驗動機及目的 6
第二章 實驗原理 9
2.1 電阻率(electrical resistivity) 9
2.1.1 電子的碰撞機制 11
2.2 熱電勢(Thermoelectric power) 13
2.2.1 Seebeck效應 13
2.2.2 Seebeck係數 14
2.3 熱傳導率 (thermal conductivity) 19
2.3.1 聲子對熱傳導率的影響 20
2.3.2 電子對熱傳導的影響 24
第三章 實驗方法 27
3.1系統與方法 27
3.1.1 低溫冷卻系統 27
3.1.2 電阻率量測方法 29
3.1.3 熱傳導率量測方法 30
3.1.4 Seebeck 係數量測方法 31
3.2 實驗控制程式 33
第四章 實驗結果與分析 41
4.1 XRD 分析 ( X-ray diffraction ) 41
4.2 XPS 分析 42
4.3電阻率對溫度的量測分析 47
4.4 熱電係數對溫度的量測分析 48
4.5 熱導率對溫度的量測分析 52
4.6 熱電優值 53
第五章 結論 56
參考文獻 57

 

W. Scott J. Electron. Mater., 3 (1974), 209
P.A . Fernandes, P.M.P. Salome, A.F.D. Cunha, J. Phys. 43 (2010) 215403.
E.J. Skoung, J.D. Cain, D.T. Morelli, J. Alloys Compd. 506 (2010) 18.
B. Qu, M. Zhang, D. Lei, Y. Zeng, Y. Chen, L. Chen, Q. Li, Y. Wang, Nanoscale 3(2011) 3646.
L.K. Samanta, Phys. Status Solidi A 100 (1987) K93.
D.T. Morelli, V. Jovovic, J.P. Heremans, Phys. Rev. Lett. 101 (2008) 035901.
C.H.L. Goodman, R.W. Douglas, Physica (Amsterdam) 20 (1954) 1107.
G.A. Slack, CRC Handbook of Thermoelectric, CRC Press, New York, 1955.
邓孝龙, Cu_2 SnSe_3系、Mo_3 Sb_7系“PGEC”型热电材料的制备及性能研究
H. Liu, X. Shi, F. Xu, L. Zhang, L. Chen, Q. Li, C. Uher, T. Day, G.J. Snyder, Nat.Mater. 11 (2012) 422.
J. Fan, H. Liu, X. Shi, S. Bai, X. Shi, L. Chen, Acta Mater. 61 (2013) 4297.
E.J. Skoung, J.D. Cain, D.T. Morelli J. Alloys Compd., 506 (2010) 18.
S. Prasad, A. Rao, B. Gahtori, S. Bathula, A. Dhar, J.S. Du, Y.K. Kuo, Mater. Res.Bull. 82 (2016) 160–166 .
Xiaoya Shi, Lili Xi, Jing Fan, Wenqing Zhang, and Lidong Chen (2010), 22, 22, 6029–6031.
Rui Ma, Guanghua Liu, Yuyang Li, Jiangtao Li, Kexin Chen, Yemao Han, Min Zhou & Laifeng Li (2018) 1439609
Xin Cheng, Zhi Li, Yonghui You, Ting Zhu, Yonggao Yan, Xianli Su, and Xinfeng Tang (2019 ) 24212–24220
Daniel D. Pollock, Thermoelectricity, (Wiley, New York, p.111-132, 1985)
D. M. Rowe, CRC Handbook of Thermoelectrics, (CRC Press, Florida, p.1-131, 1995)
G.S. Nolas, J. Sharp and H.J Goldsmid, Thermoelectrics Basic Principles and new materials developments. p42-43 (Springer, New York, 2001)
David Jiles, Introduction to the Electronic Properties of Materials, (Chapman and Hall, London, p46-48, 1994)
B.J. Christopher, Ashok Rao, P.D. Babu, G.S. Okram, J. Magn. Magn. Mater. 397 (2016) 145.
B.S. Nagaraj, Ashok Rao, P.D. Babu, G.S. Okram, Physica B: Condens. Matter 429 (2015) 10.
Chetty, M. Falmbigl, P. Rogl, P. Heinrich, E. Royanian, E. Bauer, S. Suwas, R.C.Mallik, Phys. Status Solidi A 210 (2013) 2471
C. Raju, M. Falmbigl, P. Rogl, P. Heinrich, E. Royanian, E. Bauer, Ramesh ChandraMallik, Mater. Chem. Phys. 147 (2014) 1022.
G. Rogl, A. Grytsiv, K. Yubuta, S. Puchegger, E. Bauer, C. Raju, R.C. Mallik, P. Rogl,Acta Mater. 95 (2015) 201.