Summary

使用射频磁控溅射技术制备Bi2Te3 和Sb2Te3 热电薄膜

Published: May 17, 2024
doi:

Summary

该手稿描述了一种在玻璃基板上对Bi2Te3 和Sb2Te3 热电薄膜进行射频磁控溅射的协议,该协议代表了一种可靠的沉积方法,具有广泛的应用潜力,并具有进一步发展的潜力。

Abstract

通过对热电 (TE) 材料的各种研究,薄膜配置比传统的块状 TE 具有优越的优势,包括对弯曲和柔性基板的适应性。已经探索了几种不同的薄膜沉积方法,但磁控溅射由于其高沉积效率和可扩展性而仍然具有优势。因此,本研究旨在通过射频(RF)磁控溅射法制备碲化铋(Bi2Te3)和碲化锑(Sb2Te3)薄膜。薄膜在环境温度下沉积在钠钙玻璃基板上。首先用水和肥皂洗涤基材,用甲醇、丙酮、乙醇和去离子水超声清洗10 min,用氮气和热板干燥,最后在UV臭氧下处理10 min,去除残留物后再进行涂布工艺。使用带有氩气的 Bi2Te3 和 Sb2Te3 溅射靶材,并进行预溅射以清洁靶材表面。然后,将一些干净的基板装入溅射室,并对溅射室进行真空吸尘,直到压力达到 2 x 10-5 Torr。薄膜沉积60 min,氩气流量为4 sccm,射频功率分别为75 W和30 W,Bi2Te3 和Sb2Te3。该方法产生了高度均匀的n型Bi2Te3 和p型Sb2Te3 薄膜。

Introduction

热电 (TE) 材料通过塞贝克效应1 将热能转化为电能以及通过帕尔帖冷却2 将热能转化为电能的能力吸引了相当多的研究兴趣。TE材料的转换效率由TE支腿的热端和冷端之间的温差决定。一般来说,温差越大,TE的品质因数越高,其效率越高3。TE 在工作过程中不需要额外的机械部件,不会产生任何废物或污染,使其对环境安全,并被视为绿色能源收集系统。

碲化铋、Bi2Te3 及其合金仍然是最重要的一类 TE 材料。即使在热电发电中,例如废热回收,Bi2Te3 合金也因其在高达 200 °C4 的出色效率而最常用,并且尽管各种 TE 材料的 zT 值超过 2,但在环境温度下仍然是一种出色的 TE 材料5。已发表的几篇论文研究了该材料的TE性质,表明化学计量Bi2Te3具有负塞贝克系数6,7,8表明n型性质。然而,该化合物可以通过分别与碲化锑(Sb2Te3)和硒化铋(Bi2Se3)合金化来调整为p型和n型,这可以增加它们的带隙并减少双极效应9

碲化锑,Sb2Te3 是另一种成熟的 TE 材料,在低温下具有很高的品质因数。化学计量 Bi2Te3 是具有 n 型特性的出色 TE,而 Sb2Te3 具有 p 型特性。在某些情况下,TE材料的性质往往取决于材料的原子组成,如n型富Te的Bi2Te3,而p型富Bi2Te3由于BiTe抗位受体的缺陷4。然而,由于 SbTe 反位缺陷的形成能相对较低,即使在富 Teb2Te34 中,Sb2Te3 始终是 p 型因此,这两种材料成为制造各种应用的热电发电机p-n模块的合适候选者。

目前的常规TEG由n型和p型半导体的切块锭制成,这些铸块以串联10垂直连接。由于效率低下且笨重、刚性强,它们仅用于利基领域。随着时间的流逝,研究人员开始探索薄膜结构,以获得更好的性能和应用。据报道,薄膜TE由于导热系数低11,12、材料量少且更容易与集成电路12集成,因此比其笨重的同类产品(例如更高的zT)具有优势。因此,受益于纳米材料结构的优势,薄膜热电器件的利基TE研究一直在上升13,14

薄膜的微纳加工对于获得高性能 TE 材料非常重要。为此,已经研究和开发了各种沉积方法,包括化学气相沉积15、原子层沉积1617、脉冲激光沉积181920、丝网印刷821和分子束外延22。然而,这些技术大多存在运营成本高、生长工艺复杂或材料制备复杂等问题。相反,磁控溅射是一种经济高效的方法,用于生产更致密、晶粒尺寸更小、附着力更好、均匀性高的高质量薄膜 23,24,25。

磁控溅射是基于等离子体的物理气相沉积(PVD)工艺之一,广泛应用于各种工业应用。当向靶材(阴极)施加足够的电压时,溅射工艺起作用,来自辉光放电等离子体的离子轰击靶材,不仅释放二次电子,还释放阴极材料的原子,最终影响基板表面并凝结成薄膜。溅射工艺于 1930 年代首次商业化,并于 1960 年代得到改进,由于其能够使用直流 (DC) 和射频溅射沉积各种材料而引起了极大的兴趣26,27。磁控溅射通过利用磁场克服了低沉积速率和高基板加热冲击。强磁体将等离子体中的电子限制在目标表面或附近,并防止损坏形成的薄膜。这种配置保留了沉积薄膜28的化学计量和厚度均匀性。

使用磁控溅射法制备Bi2Te3和Sb2Te3热电薄膜也得到了广泛的研究,在工艺中加入了掺杂4,29,30和退火31等技术,导致不同的性能和质量。Zheng等[32]的研究采用热诱导扩散法扩散了分别溅射的Ag掺杂Bi和Te层。该方法可以精确控制薄膜的成分,并且通过热感应扩散Te可以防止Te挥发。薄膜的性能也可以通过溅射前的预涂层工艺33来增强,由于高载流子迁移率,导致更好的导电性,从而增强功率因数。除此之外,Chen等[34]的研究通过硒化后扩散反应法掺杂Se,提高了溅射Bi2Te3的热电性能。在此过程中,Se 蒸发并扩散到 Bi-Te 薄膜中形成 Bi-Te-Se 薄膜,其功率因数比未掺杂的 Bi2Te3 高 8 倍。

本文介绍了射频磁控溅射技术在玻璃基板上沉积Bi2Te3 和Sb2Te3 薄膜的实验装置和程序。溅射以自上而下的配置进行,如 图1中的原理图所示,阴极与基板法线成一定角度安装,导致基板的等离子体更加集中和收敛。采用FESEM、EDX、霍尔效应和塞贝克系数等方法系统表征薄膜表面形貌、厚度、成分和热电性能。

Figure 1
图 1:自上而下的配置溅射示意图。 该图的设计符合本研究可用的实际溅射配置,但不是按比例设计的,包括从顶部观察要溅射的玻璃基板的布置。 请点击这里查看此图的较大版本.

Protocol

1. 基材制备 用无绒布擦拭玻璃基材,以去除松散的污垢或碎屑。用水和肥皂清洗玻璃基板,用刷子擦洗玻璃上的任何污垢。 在烧杯中制备下面列出的所有溶剂,将玻璃基板浸入溶剂中,并在37kHz下相应地超声处理。在80°C下制备甲醇10分钟;丙酮在80°C下10分钟,乙醇在80°C下10分钟,蒸馏(DI)水在80°C下20分钟。注意: 在通风橱中处理高挥发性化学品。 用镊子…

Representative Results

使用FESEM记录沉积的Bi2Te3 和Sb2Te3 薄膜的横截面显微照片,分别如 图3A 和 图3B所示。整片表面显得均匀光滑。很明显,Bi2Te3 薄膜的晶粒是六边形的,符合Bi2Te3 的晶体结构,而Sb2Te3 薄膜的晶粒由细小的圆形晶粒组成,与Amirghasemi等人36报道的相似。两个?…

Discussion

本文介绍的技术在设置设备和实施方面没有重大困难。但是,需要强调几个关键步骤。如协议的步骤2.2.10所述,最佳真空条件是生产污染较少的高质量薄膜的关键,因为真空可以去除腔室37中的残留氧气。氧气的存在会导致薄膜出现裂纹,称为应力开裂,表明高真空系统在溅射过程中的重要性38。这也减少了原子39 从靶材到基板的运动中与残余…

Declarações

The authors have nothing to disclose.

Acknowledgements

作者要感谢马来西亚国民大学研究基金的财政支持:UKM-GGPM-2022-069 进行这项研究。

Materials

Acetone Chemiz (M) Sdn. Bhd. 1910151 Liquid, Flammable
Antimony Telluride, Sb2Te3 China Rare Metal Material Co.,Ltd C120222-0304 Diameter 50.8 mm, Thickness 6.35 mm, 99.999% purity
Bismuth Telluride, Bi2Te3 China Rare Metal Material Co.,Ltd CB151208-0501 Diameter 50.8 mm, Thickness 4.25 mm, 99.999% purity
Ethanol Chemiz (M) Sdn. Bhd. 2007081 Liquid, Flammable
Field Emission Scanning Electron Microscope Zeiss MERLIN Equipped with EDX
Hall effect measurement system Aseptec Sdn. Bhd. HMS ECOPIA 3000
Handheld digital multimeter Prokits Industries Sdn. Bhd. 303-150NCS
HMS-3000 Aseptec Sdn Bhd. HMS ECOPIA 3000 Hall effect measurement software
Linseis_TA Linseis Messgeräte GmbH LSR-3 Linseis thermal analysis software
Methanol Chemiz (M) Sdn. Bhd. 2104071 Liquid, Flammable
RF-DC magnetron sputtering Kurt J. Lesker Company Customized hybrid system
Seebeck coefficient measurement system Linseis Messgeräte GmbH LSR-3
SmartTiff Carl Zeiss Microscopy Ltd SEM image thickness measurement software
Ultrasonic bath Fisherbrand FB15055
UV ozone cleaner Ossila Ltd L2002A3-UK

Referências

  1. Ochieng, A. O., Megahed, T. F., Ookawara, S., Hassan, H. Comprehensive review in waste heat recovery in different thermal energy-consuming processes using thermoelectric generators for electrical power generation. Proc Safety Environ Prot. 162, 134-154 (2022).
  2. Shilpa, M. K., et al. A systematic review of thermoelectric Peltier devices: Applications and limitations. Fluid Dyn Mater Proc. 19 (1), 187-206 (2022).
  3. Jiang, W., Huang, Y. . Thermoelectric technologies for harvesting energy from pavements. Eco-efficient Pavement Construction Materials. , (2020).
  4. Witting, I. T., et al. The thermoelectric properties of Bismuth telluride. Adv Elect Mater. 5 (6), 1-20 (2019).
  5. Isotta, E., et al. Towards low cost and sustainable thin film thermoelectric devices based on quaternary chalcogenides. Adv Funct Mater. 32 (32), 2202157 (2022).
  6. Yonezawa, S., Tabuchi, T., Takashiri, M. Atomic composition changes in bismuth telluride thin films by thermal annealing and estimation of their thermoelectric properties using experimental analyses and first-principles calculations. J Alloys Comp. 841, 155697 (2020).
  7. Fan, P., et al. High-performance bismuth telluride thermoelectric thin films fabricated by using the two-step single-source thermal evaporation. J Alloys Comp. 819, 153027 (2020).
  8. Amin, A., et al. Screen-printed bismuth telluride nanostructured composites for flexible thermoelectric applications. JPhys Energy. 4 (2), 024003 (2022).
  9. Witting, I. T., Ricci, F., Chasapis, T. C., Hautier, G., Snyder, G. J. The thermoelectric properties of n-type Bismuth telluride: Bismuth selenide alloys Bi2Te3−xSex. Pesquisa. 2020, 4361703 (2020).
  10. Shi, X. L., Zou, J., Chen, Z. G. Advanced thermoelectric design: From materials and structures to devices. Chem Rev. 120 (15), 7399 (2020).
  11. Ferrando-Villalba, P., et al. Measuring device and material ZT in a thin-film Si-based thermoelectric microgenerator. Nanomaterials. 9 (4), 653 (2019).
  12. Karthikeyan, V., et al. Wearable and flexible thin film thermoelectric module for multi-scale energy harvesting. J Power Sources. 455, 227983 (2020).
  13. Guo, X., He, Y. Mathematical modeling and optimization of platform service supply chains: A literature review. Mathematics. 10 (22), 4307 (2022).
  14. Syafiq, U., et al. Facile and low-cost fabrication of Cu/Zn/Sn-based ternary and quaternary chalcogenides thermoelectric generators. ACS Appl Ener Mater. 5 (5), 5909-5918 (2022).
  15. Newbrook, D. W., et al. Improved thermoelectric performance of Bi2Se3 alloyed Bi2Te3 thin films via low pressure chemical vapour deposition. J Alloys Comp. 848, 156523 (2020).
  16. Lim, S. S., et al. Carrier modulation in Bi2Te3-based alloys via interfacial doping with atomic layer deposition. Coatings. 10 (6), 1-8 (2020).
  17. Chen, X., Baumgart, H. Advances in atomic layer deposition (ALD) nanolaminate synthesis of thermoelectric films in porous templates for improved seebeck coefficient. Materials. 13 (6), 1-20 (2020).
  18. Darwish, A. M., et al. Thermoelectric properties of Al-doped ZnO composite films with polymer nanoparticles prepared by pulsed laser deposition. Composites Part B: Engineering. 167, 406-410 (2019).
  19. Symeou, E., Nicolaou, C., Kyratsi, T., Giapintzakis, J. Enhanced thermoelectric properties in vacuum-annealed Bi0.5Sb1.5Te3 thin films fabricated using pulsed laser deposition. J Appl Phys. 125 (21), 0 (2019).
  20. Wudil, Y. S., Gondal, M. A., Rao, S. G., Kunwar, S., Alsayoud, A. Q. Substrate temperature-dependent thermoelectric figure of merit of nanocrystalline Bi2Te3 and Bi2Te2.7Se0.3 prepared using pulsed laser deposition supported by DFT study. Ceramics Int. 46 (15), 24162-24172 (2020).
  21. Sousa, V., et al. High Seebeck coefficient from screen-printed colloidal PbSe nanocrystals thin film. Materials. 15 (24), 8805 (2022).
  22. Rao, D., et al. High mobility and high thermoelectric power factor in epitaxial ScN thin films deposited with plasma-assisted molecular beam epitaxy. Appl Phys Lett. 116 (15), 152103 (2020).
  23. Hu, B., et al. Advances in flexible thermoelectric materials and devices fabricated by magnetron sputtering. Small Sci. , 2300061 (2023).
  24. Gudmundsson, J. T. Physics and technology of magnetron sputtering discharges. Plasma Sources Science and Technology. 29 (11), 113001 (2020).
  25. Tani, J. I., Ishikawa, H. Thermoelectric properties of Mg2Sn thin films fabricated using radio frequency magnetron sputtering. Thin Solid Films. 692, 137601 (2019).
  26. Gudmundsson, J. T., Lundin, D. Introduction to magnetron sputtering. High Power Impulse Magnetron Sputtering. , 1-48 (2019).
  27. Hossain, E. S., et al. Fabrication of Cu2SnS3 thin film solar cells by sulphurization of sequentially sputtered Sn/CuSn metallic stacked precursors. Solar Energy. 177, 262-273 (2019).
  28. Maurya, D. K., Sardarinejad, A., Alameh, K. Recent developments in R.F. magnetron sputtered thin films for pH sensing applications-an overview. Coatings. 4 (4), 756-771 (2014).
  29. Ahmad, F., et al. Effect of doping and annealing on thermoelectric properties of Bismuth telluride thin films. J Electron Mater. 49 (7), 4195-4202 (2020).
  30. Zhou, Y., Li, L., Tan, Q., Li, J. F. Thermoelectric properties of Pb-doped bismuth telluride thin films deposited by magnetron sputtering. J Alloys Comp. 590, 362-367 (2014).
  31. Takayama, K., Takashiri, M. Multi-layered-stack thermoelectric generators using p-type Sb2Te3 and n-type Bi2Te3 thin films by radio-frequency magnetron sputtering. Vacuum. 144, 164-171 (2017).
  32. Zheng, Z. H., et al. Harvesting waste heat with flexible Bi2Te3 thermoelectric thin film. Nat Sustain. 6 (2), 180-191 (2023).
  33. Zhang, J., et al. Effects of Si Substrates with Variable Initial Orientations on the Growth and Thermoelectric Properties of Bi-Sb-Te Thin Films. Nanomaterials. 13 (2), 257 (2023).
  34. Chen, Y. X., et al. Realizing high thermoelectric performance in n-type Bi2Te3 based thin films via post-selenization diffusion. J Mater. 9 (4), 618-625 (2023).
  35. Zakaria, Z., et al. Effects of sulfurization temperature on Cu2ZnSnS4 thin film deposited by single source thermal evaporation method. Jpn J Appl Phys. 54, (2015).
  36. Amirghasemi, F., Kassegne, S. Effects of RF magnetron sputtering deposition power on crystallinity and thermoelectric properties of Antimony telluride and Bismuth telluride thin films on flexible substrates. J Electron Mater. 50 (4), 2190-2198 (2021).
  37. Baptista, A., et al. On the physical vapour deposition (PVD): Evolution of magnetron sputtering processes for industrial applications. Procedia Manu. 17, 746-757 (2018).
  38. Heu, R., Shahbazmohamadi, S., Yorston, J., Capeder, P. Target material selection for sputter coating of SEM samples. Microscopy Today. 27 (4), 32-36 (2019).
  39. Marquardt, N. . Introduction to the principles of vacuum physics. , 1-24 (1999).
  40. Ayachi Omar, A., Kashapov, N. F., Luchkin, A. G., Ayachi Amor, A., Ayachi Amar, A. Effect of cooling system design on the heat dissipation of the magnetron sensitive components with rectangular target during sputtering by Ar+. Results in Engineering. 16, 100696 (2022).
  41. Sharma, R., Sharma, S. Why sputtering target cracks. Zenodo. , (2020).
  42. Huang, P. C., et al. The effect of sputtering parameters on the film properties of molybdenum back contact for CIGS solar cells. Int J Photoener. 2013, 390824 (2013).
  43. Yin, Z., et al. Effect of sputtering process parameters on the uniformity of copper film deposited in micro-via. J Mater Res Technol. 25, 5249-5259 (2023).
  44. Ejaz, H., Hussain, S., Zahra, M., Saharan, Q. M., Ashiq, S. Several sputtering parameters affecting thin film deposition. J Appl Chem Sci Int. 13 (3), 41-49 (2022).
  45. Mandal, P., Singh, U. P., Roy, S. A review on the effects of PVD RF sputtering parameters on rare earth oxide thin films and their applications. IOP Conf. Ser: Mater Sci Eng. 1166 (1), 012022 (2021).
  46. Sahu, B. P., Sarangi, C. K., Mitra, R. Effect of Zr content on structure property relations of Ni-Zr alloy thin films with mixed nanocrystalline and amorphous structure. Thin Solid Films. 660, 31-45 (2018).
  47. Sahu, B. P., Dutta, A., Mitra, R. Influence of substrate bias voltage on structure and properties of DC magnetron sputtered Ni-Zr alloy thin films. J Mater Res. 35 (12), 1543-1555 (2020).
  48. Yaqub, T. B., Vuchkov, T., Sanguino, P., Polcar, T., Cavaleiro, A. Comparative study of DC and RF sputtered MoSe2 coatings containing carbon-An approach to optimize stoichiometry, microstructure,crystallinity and hardness. Coatings. 10 (2), 133 (2020).
  49. Kim, J., et al. Effect of IGZO thin films fabricated by Pulsed-DC and RF sputtering on TFT characteristics. Mater Sci Semicond Proc. 120, 105264 (2020).
  50. Panepinto, A., Snyders, R. Recent advances in the development of nano-sculpted films by magnetron sputtering for energy-related applications. Nanomaterials. 10 (10), 1-27 (2020).
  51. Lenis, J. A., Bejarano, G., Rico, P., Ribelles, J. L. G., Bolívar, F. J. Development of multilayer Hydroxyapatite – Ag/TiN-Ti coatings deposited by radio frequency magnetron sputtering with potential application in the biomedical field. Surf Coat Tech. 377, 124856 (2019).
  52. Wang, M., Chen, Y., Gao, B., Lei, H. Electrochromic properties of nanostructured WO3 thin films deposited by glancing-angle magnetron sputtering. Adv Electron Mater. 5 (5), 1-7 (2019).

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Ahmad Musri, N., Putthisigamany, Y., Chelvanathan, P., Ahmad Ludin, N., Md Yatim, N., Syafiq, U. Fabrication of Bi2Te3 and Sb2Te3 Thermoelectric Thin Films using Radio Frequency Magnetron Sputtering Technique. J. Vis. Exp. (207), e66248, doi:10.3791/66248 (2024).

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