本研究主要目的為探討鎂對於氧化鋅奈米材料在焦電性質上的影響，以及焦電奈米發電機的製備時需要注意與解決的問題。選用氧化鋅作為主要材料的原因是其無毒無汙染，與常見的鐵電型陶瓷焦電材料，如：PZT、PbTiO3…鋅及鎂幾乎對人體和大部分環境無害，加上在製程上有許多可供選擇的原材料，可以充足且穩定的條件來調整製程參數，使得精細的奈米結構能被控制與製備。
本研究將以RF磁控濺鍍製備氧化鋅薄膜，再以水熱法製備氧化鋅奈米柱陣列，並透過加入不同濃度之鎂前驅物來摻雜Mg，來提升奈米柱陣列之內部應變，藉此了解Mg摻雜對於氧化鋅焦電奈米發電機輸出之影響。為了改良元件的輸出電壓，本實驗研發出一種新的方法，能夠以銀膠和丙酮於奈米柱陣列上快速製備銀電極，解決了元件製作時的主要問題──電極原子穿透奈米柱陣列形成短路。運用此法和一些改良後，成功提升奈米發電機的元件輸出電壓約170倍，焦電係數相差63倍。
將奈米發電機輸出電壓之波形和大小穩定後，使用SEM確認每一個試片之厚度，並經由其他文獻推導出一個新的公式來計算焦電係數，此公式以輸出電壓為主，對比舊的焦電係數公式使用電流來計算，理應更能代表以電壓輸出為主的焦電效應。
最後藉由比較輸出資料可以了解到：1.元件製程影響焦電奈米發電機的輸出劇烈 2.在水熱法中使用0.05M Mg前驅物進行摻雜後，元件輸出電壓出現大幅上升，由純ZnO的0.17mV增加至2mV，焦電係數則是從純ZnO的4.6(V/K‧m)增加至122.7(V/K‧m)。透過SEM、XRD和EDS等儀器的測量結果得以了解，Mg的摻雜必須提升到特定濃度之後，奈米柱陣列的形貌改變，焦電奈米發電機的輸出才會明顯提升。透過此實驗結果，展示出元件製程如何影響焦電奈米發電機之輸出，並證實了摻雜鎂能夠有效提升氧化鋅焦電奈米發電機的輸出電壓，提供一個標準製程使未來製作其他焦電奈米發電機時可以參考。

As a environment-friendly pyroelectric material, ZnO has huge potential for waste heat/cold recovery. In this paper, ZnO and Mg_0.4 〖Zn〗_0.6 O thin film are coating on Si substrate as seed layer by sputter. Nanorods array, the main pyroelectric material is synthesized by hydrothermal method. All crystal orientation and surface morphology is checked by XRD and SEM. To fabricating reliable nanogenerator, we apply several modification to optimize nanogenerator device, including a new method to coat Ag electrode. We find that device structure will increase output voltage from 1μV to 170μV and pyroelectric coefficient from 0.051(V/K‧m) to 4.6(V/K‧m). After stabilizing device structure, Mg is chosen as the dopant to improving the output performance of ZnO based pyroelectric nanogenerator. Because Mg^(2+) has the same valence as Zn^(2+), there will be no more carriers, which will enhance screen effect after doping. Comparing to pure ZnO, high Mg precursor concentration sample shows a huge enhancement on output voltage and pyroelectric coefficient. Therefore, Mg doping is considered as a effective way to improve the performance of ZnO pyroelectric nanogenerator.

1. Chian-ping Ye, Takashi Tamagawa, D. L. Poll, ＂Experimental studies on primary and secondary pyroelectric effects in Pb(ZrxTi1−x)O3, PbTiO3, and ZnO thin films＂, Journal of Applied Physics Vol. 70 No. 10, 1991
2. Ya Yang , Jong Hoon Jung , Byung Kil Yun, ＂Flexible Pyroelectric Nanogenerators using a Composite Structure of Lead-Free KNbO 3 Nanowires＂,Advenced Materials Vol. 24 5357–5362, 2012
3. Ya Yang, Wenxi Guo, Zhong Lin Wang, ＂Pyroelectric Nanogenerators for Harvesting Thermoelectric Energy＂,Nano Letter 2833–2838, 2012
4. Farshad Farahbod, Sara Farahmand, ＂Empirical Investigation of Heating and Kinematic Performance of ZnO Nano Fluid in a Heat Pipe＂, Journal of Nanofluids Vol. 6(1) pp. 128-135, 2017
5. B. Meyer, Dominik Marx, ＂Density-functional study of the structure and stability of ZnO surfaces＂, Physical Review B Vol. 67 035403, 2003
6. TAN Rui-qin, ZHANG Yu-Long, YANG Ye, ＂Pyroelectric properties of ZnO-based nanostructured polycrystalline ceramics＂, Proceedings of Society of Photo-Optical Instrumentation Engineers Vol. 7381 738120-1 ,2009
7. Shiva Hullavarad, Nilima Hullavarad, ＂ZnO and MgZnO Alloys Redefine UV Sensing＂, Laser Focus World, 2010
8. M. Niranjana, L. Yesappa, S. P. Ashokkumar, ＂Optical and electrical studies of vanadium pentoxide doped polyaniline composite＂,AIP Conference Proceedings 1832 040010, 2017
9. Charles Kittel, ＂Introduction To Solid State Physics 8th Edition＂, Wiley, 2016
10. S. Kasap, P. Capper (Eds.), ＂Springer Handbook of Electronic and Photonic Materials＂, Springer Cham , 2017
11. C. H. Ahn, K. M. Rabe, J.-M. Triscone, ＂Ferroelectricity at the Nanoscale: Local Polarization in Oxide Thin Films and Heterostructures＂, Science Vol.303 Issue 5657 pp. 488-491, 2004
12. Hongying He, Xin Lu, Emil Hanc, ＂Advances in lead-free pyroelectric materials: a comprehensive review＂, Journal of Materials Chemistry C Vol. 8 1494, 2020
13. R. D. Shannon, “Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides,”Acta Crystallographica 32, no. 5, 1976
14. David Brewster, ”Observations on the pyro-electricity of minerals”, Edinburgh : William Blackwood, 1824
15. S. B. Lang, ”A 2400 year history of pyroelectricity: from Ancient Greece to exploration of the solar system”, British Ceramic Transactions Vol. 103 No. 2, 2004
16. Jian Liu, Maria V. Fern_andez-Serra, Philip B. Allen, Stony Brook, ”A first-principles study of pyroelectricity in GaN and ZnO”, Physical Review B 93 081205(R), 2016
17. D.L. Polla, R.S. Muller, and R.M. White, ”PYROELECTRIC PROPERTIES AND APPLICATIONS OF SPUTTERED ZINC-OXIDE THIN FILMS ULTRASONICS SYMPOSIUM”, Institute of Electrical and Electronics Engineers Ultrasonics Symposium, 1985
18. Qingguo Chi, Jiufeng Dong, Changhai Zhang, ”Highly (100)-oriented sandwich structure of (Na0.85K0.15)0.5Bi0.5TiO3 composite films with outstanding pyroelectric properties”, Journal of Materials Chemistry C Vol.4 4442, 2016
19. Werner Känzig, ”Ferroelectrics and Antiferroelectrics”, Academic Press, 1964
20. Gang Liu, Shujun Zhang, Wenhua Jiang, ”Losses in ferroelectric materials”, Materials Science and Engineering R 89 1–48 ,2015
21. Farshad Farahbod, Sara Farahmand, ”Empirical Investigation of Heating and Kinematic Performance of ZnO Nano Fluid in a Heat Pipe”, Journal of Nanofluids Vol. 6(1) pp. 128-135, 2017
22. B. Meyer, Dominik Marx, ”Density-functional study of the structure and stability of ZnO surfaces”, Physical Review B 67 035403, 2003
23. Gorczyca, H. Teisseyre, T. Suski, ”Structural and electronic properties of wurtzite MgZnO and BeMgZnO alloys and their thermodynamic stability”, Journal of Applied Physics 120, 215704 ,2016
24. Sunandan Baruah, Joydeep Dutta, ”Hydrothermal growth of ZnO Nanostructures”, Science and Technology of Advanced Materials 10 013001, 2009
25. Hao Tang, Jack C. Chang, Yueyue Shan, and Shuit-Tong Lee, ”Surfactant-Assisted Alignment of ZnO Nanocrystals to Superstructures”, The Journal of Physical Chemistry B Vol.112 4016-4021 2008
26. YongQing Duan, YongAn Huang, ZhouPing Yin, “Non-wrinkled, highly stretchable piezoelectric devices by electrohydrodynamic direct-writing”, Nanoscale Vol.6 3289–3295, 2014
27. Chieh Chang, Van H. Tran, Junbo Wang, “Direct-Write Piezoelectric Polymeric Nanogenerator with High Energy Conversion Efficiency”, Nano Letter Vol.10 726-731, 2010
28. Behzad Mohammadi, Ali Akbar Yousefi, Samad Moemen Bellah, “Effect of tensile strain rate and elongation on crystalline structure and piezoelectric properties of PVDF thin films”, Polymer Testing Vol.26 pp.42–50, 2007
29. G. Heiland, H. Ibach, “PYROELECTRICITY OF ZINC OXIDE”, Solid State Communications Vol. 4 pp.353-354, 1966
30. Long Gu, Jinmei Liu, Nuanyang Cui,” Enhancing the current density of a piezoelectric nanogenerator using a three-dimensional intercalation electrode”, Nature Comunications 11:1030, 2020
31. TAN Rui-qin, ZHANG Yu-Long, YANG Ye, “Pyroelectric Properties of ZnO-based Nano-structured Polycrystalline Ceramics”, Proceedings of Society of Photo-Optical Instrumentation Engineers Vol. 7381 738120-1, 2009
32. Gerald Gerlach, Dmitry Shvedov, Volkmar Norkus, ” Packaging Influence on Acceleration Sensitivity of Pyroelectric Infrared Detectors”, Institute of Electrical and Electronics Engineers Ultrasonics Symposium 0-7803-8620-5, 2004
33. D.L. Polla, R.S. Muller, R.M. White, “PYROELECTRIC PROPERTIES AND APPLICATIONS OF SPUTTERED ZINC-OXIDE THIN FILMS”, Institute of Electrical and Electronics Engineers Ultrasonics Symposium 0090-5607/85/0000-0495, 1985
34. Nagesh Kumar · G.D. Varma · R. Nath · A.K. Srivastava,” Synthesis of ordered ZnO nanowire arrays from aqueous solution using AAO template”, Applied Physics A 104:1169–1174, 2011
35. Minoli K. Pathirane, Hadi Hosseinzadeh Khaligh, Irene A. Goldthorpe, ” Al-doped ZnO/Ag-nanowire Composite Electrodes for Flexible 3-Dimensional Nanowire Solar Cells”, Scientific Reports 7:8916, 2017
36. Kwi-Il Park, Soo Bin Bae, Seong Ho Yang, “Lead-free BaTiO3 nanowires-based flexible nanocomposite generator”, Nanoscale Vol.6 8962, 2014
37. A. D. Bykhovski, V. V. Kaminski, M. S. Shur, “Pyroelectricity in gallium nitride thin films”, Applied Physics Letters 69 (21), 1996
38. K. H. Tam, C. K. Cheung, Y. H. Leung, “Defects in ZnO Nanorods Prepared by a Hydrothermal Method”, The Journal of Physical Chemistry B 110 20865-20871, 2006
39. Alexandr Baronov, Kevin Bufkin, Dan W. Shaw, “A simple model of burst nucleation”, Physical Chemistry Chemical Physics 17 20846, 2015
40. Jörg Polte, “Fundamental growth principles of colloidal metal nanoparticles – a new perspective”, CrystEngComm 17(36), 2015
41. Sidney B. Lang, “Pyroelectric Coefficient of Lithium Sulfate Monohydrate (4.2-320 K)”, Physical Review B Vol.4 Number 10, 1971
42. S. Satapathy, P. Kumar. Gupta, K. BabiRaju. Varma, “Enhancement of nonvolatile polarization and pyroelectric sensitivity in Lithium tantalate (LT)/ Poly (vinylidene fluoride) (PVDF) nano composite”, Journal of Physics D Applied Physics 42(5), 2008
43. Ronggui Yang, Gang Chen, ”Thermal conductivity of simple and tubular nanowire composites in the longitudinal direction”, Physical Review B 72 125418, 2005
44. Fabio Bernardini, Vincenzo Fiorentini, “Spontaneous polarization and piezoelectric constants of III-V nitrides”, Physical Review B Vol.56, Number 16, 1997
45. B. Szigeti, “Temperature Dependence of Pyroelectricity”, Physical Review Letters Vol.35 Number 22, 1975
46. K.-H. Chew, F. G. Shin, B. Ploss, ” Primary and secondary pyroelectric effects of ferroelectric 0-3 composites”, Journal of Applied Physics Vol.94 Number 2 2003
47. K S Tan, W C Gan, T S Velayutham, “Pyroelectricity enhancement of PVDF nanocomposite thin films doped with ZnO nanoparticles”, Smart Materials and Structures 23 125006, 2014
48. Juyoung Kim, Satoru Yamanaka, Akira Nakajima, “Pyroelectric power generation with ferroelectrics (1-x)PMN-xPT”, Ferroelectrics Vol.512 92–99, 2017
49. Guojun Zhou , Hao Liu , Kairen Chen, “The origin of pyroelectricity in tourmaline at varying temperature”, Journal of Alloys and Compounds 744 328-336, 2018
50. Satoru Yamanaka, Juyoung Kim, Akira Nakajima, “Relationship Between the Material Properties and Pyroelectric-Generating Performance of PZTs”, Advanced Sustainable Systems Vol.1 1600020, 2017
51. R W Whatmore, “Pyroelectric devices and materials”, Reports on Progress in Physics 49 1335-1386, 1986
52. Shishir Pandya, Joshua Wilbur, Jieun Kim, “Pyroelectric energy conversion with large energy and power density in relaxor ferroelectric thin films”, Nature Materials Vol.17 432–438, 2018
53. Qingguo Chi, Jiufeng Dong, Changhai Zhang, “Highly (100)-oriented sandwich structure of (Na0.85K0.15)0.5Bi0.5TiO3 composite films with outstanding pyroelectric properties”, Journal of Materials Chemistry C 4 4442, 2016
54. Krystian Mistewicz, Marcin Jesionek, Marian Nowak, “SbSeI pyroelectric nanogenerator for a low temperature waste heat recovery”, Nano Energy 64 103906, 2019
55. Dohwan Kim , Keun Young Lee , Manoj Kumar Gupta, “Self-Compensated Insulating ZnO-Based Piezoelectric Nanogenerators”, Advanced Functional Materials 24, 6949–6955, 2014
56. Chun-Ching Hsiao , An-Shen Siao, Jing-Chih Ciou, “Improvement of Pyroelectric Cells for Thermal Energy Harvesting”, Sensors 12 534-548, 2012
57. A. N. Morozovska, E. A. Eliseev, G. S. Svechnikov, “Pyroelectric response of ferroelectric nanowires: Size effect and electric energy harvesting”, Journal of Applied Physics 108 042009, 2010
58. S.-M. Lee, David G. Cahill, “Thermal conductivity of sputtered oxide films”, Physical Review B Vol.52 Number 1, 1995
59. Jing Zhao, Rongfeng Zhu, Qiuxiang Du, “Surface and thickness effect on the ferroelectric, dielectric and pyroelectric properties of Mn-doped Pb(Mg1/3Nb2/3)O3─0.28PbTiO3 single crystals”, Journal of Alloys and Compounds Vol.816 5 152500, 2020
60. Chun-Ching Hsiao1,, Sheng-Wen Huang, Rwei-Ching Chang, “Temperature Field Analysis for ZnO Thin-Film Pyroelectric Devices with Partially Covered Electrode”, Sensors and Materials Vol. 24 No. 8 421–441, 2012
61. Shuhua Wang , Zhong Lin Wang , Ya Yang, ” A One-Structure-Based Hybridized Nanogenerator for Scavenging Mechanical and Thermal Energies by Triboelectric–Piezoelectric–Pyroelectric Effects”, Advenced Materials 28 2881–2887, 2016
62. Mahipal Singh , Madan Singh, “Thermal Expansion in Zinc Oxide Nanomaterials”, Nanoscience and Nanotechnology Research, Vol. 1, No. 2, 27-29, 2013
63. Daotong You, Chunxiang Xu, Wei Zhang, “Photovoltaic-pyroelectric effect coupled broadband photodetector in selfpowered ZnO/ZnTe core/shell nanorod arrays”, Nano Energy 62 310–318, 2019
64. Ch. G. WU, W. L. ZHANG, Y. R. LI, “Measurement of Induced Pyroelectric Coefficient Using Dynamic Method:Theory and Experiments”, Japanese Journal of Applied Physics Vol. 45 Number 4A pp. 2674–2677, 2006
65. Qingping Wang, Chris R. Bowen, Rhodri Lewis, ” Hexagonal boron nitride nanosheets doped pyroelectric ceramic composite for high-performance thermal energy harvesting”, Nano Energy 60 144–152, 2019
66. Kewei Zhang, Yuanhao Wang, Ya Yang, “Structure Design and Performance of Hybridized Nanogenerators”, Advanced Functional Materials 1806435, 2018