Electropulsing induced phase transformation and crystal orientation change and their effects on electrical conductivity, THz reflection and surface roughness of thin-films of Al2O3 (2 wt%) doped ZnO were studied using XRD, SEM, AFM and Thz spectroscopy techniques. AZO-2 thin-films showed an effective response in THz spectroscopy under electropulsing. Electropulsing induced circular preferred crystal orientation changes and phase transformations were observed. The preferred crystal orientation changes accompanying decrease in stress and the secondary phase precipitation favored enhancing conductivity and THz reflection of the AZO-2 thin-films. After adequate electropulsing, both THz reflection and electrical conductivity of the thin-films were enhanced by 22.8% and 6.8%, respectively; meanwhile surface roughness reduced. The property responses of electropulsing are discussed from point view of microstructural change and dislocation dynamics.
References
[1]
Parthiban, S., et al. (2010) Investigations on High Visible to Near Infrared Transparent and High Mobility Mo Doped In2O3 Thin Films Prepared by Spray Pyrolysis Technique. Solar Energy Materials and Solar Cells, 94, 406-412.
http://dx.doi.org/10.1016/j.solmat.2009.10.017
[2]
Kelmer, H. (2012) Past Achievements and Future Challenges in Development of Optically Transparent Electrodes. Nature Phontonics, 6, 808-816.
[3]
Fortunato, E. (2012) Oxide Semiconductor Thin-Film Transistor: A Review of Recent Advances. Advanced Materials, 24, 2945-2986. http://dx.doi.org/10.1002/adma.201103228
[4]
Castaneda, L. (2011) Present Status of Development and Application of Transparent Conductors Oxide Thin Solid Films. Materials Sciences and Applications, 2, 1233-1242. http://dx.doi.org/10.4236/msa.2011.29167
[5]
Afluga, P., Sittingera, V., Ruskea, F., Szyszkaa, B. and Dittmarb, G. (2004) Optical Characterization of Aluminum-Doped Zinc Oxide Films by Advanced Dispersion Theories. Thin Solid Films, 455-456, 201-206.
http://dx.doi.org/10.1016/j.tsf.2004.01.006
[6]
Hiramatsu, M., Kmaeda, I., Horio, N. and Nawata, M. (1998) Trasparent Conducting ZnO Thin Films Prepared by XeCl Excimer Laser Ablation. Journal of Vacuum Science & Technology A, 16, 669-673.
http://dx.doi.org/10.1116/1.581085
[7]
Nahata, A., Auston, D.H., Heinz, T.F. and Wu, C. (1996) Coherent Detection of Freely Propagating Terahertz Radiation by Electro-Optic Sampling. Applied Physics Letters, 68, 150-152. http://dx.doi.org/10.1063/1.116130
[8]
Hangyo, M., Nagashima, T. and Nashima, S. (2002) Spectroscopy by Pulsed Terahertz Radiation. Measurement Science and Technology, 13, 1727-1738. http://dx.doi.org/10.1088/0957-0233/13/11/309
[9]
Ferguson, B., et al. (2002) Materials for Terahertz Science and Technology. Nature Materials, 1, 6-33.
http://dx.doi.org/10.1038/nmat708
[10]
Beard, M.C., Turner, G.M. and Schmuttenmaer, C.A. (2002) Terahertz Spectroscopy. Journal of Physical Chemistry B, 106, 7146-7159. http://dx.doi.org/10.1021/jp020579i
[11]
Brunner, F.D.J., Schneider, A. and Gunter, P. (2009) A Terahertz Time-Domain Spectrometer for Simultaneous Transmission and Reflection Measurements at Normal Incidence. Optics Express, 17, 20684-20693.
http://dx.doi.org/10.1364/OE.17.020684
[12]
Lai, W.E., Zhang, H.W., Zhu, Y.H. and Wen, Q.Y. (2013) A Novel Method of Terahertz Spectroscopy and Imaging in Reflection Geometry. Applied Spectroscopy, 67, 36-39. http://dx.doi.org/10.1366/12-06713
[13]
Khazan, M., Meissner, R. and Ingrid, W. (2001) Convertible Transmission Reflection Time-Domain Terahertz Spectrometer. Review of Scientific Instruments, 72, 8. http://dx.doi.org/10.1063/1.1384433
Gromov, V.E., Zuev, L.B., Bazaikin, V.I. and Tsellermaer, V.Y. (1996) Laws of Electrical Stimulation of Plastic Development of Metals and Alloys at Various Structural Levels. Russian Physics Journal, 39, 237-261.
http://dx.doi.org/10.1007/BF02067645
[16]
Qin, R.S. and Zhou, B.L. (1998) Effect of Electric Current Pulses on Grain Size in Castings (Overview). International Journal of Non-Equilibrium Processing, 11, 77-86.
[17]
Stolyarov, V.V. (2009) Deformability and Nanostructuring of TiNi Shape-Memory Alloys during Electroplastic Rolling. Materials Science and Engineering: A, 503, 18-20. http://dx.doi.org/10.1016/j.msea.2008.01.094
[18]
Conrad, H. (2000) Effect of Electric Current on Solid-State Phase Transformations in Metals. Materials Science and Engineering A, 287, 227-237.
[19]
Zhu, Y.H., Lee, W.B, To, S., Liu, X.M., Jiang, Y.B. and Tang, G.Y. (2009) Effect of Dynamic Electropulsing on Microstructure and Elongation of a Zn-Al Based Alloy. Materials Science and Engineering: A, 501, 125-132.
http://dx.doi.org/10.1016/j.msea.2008.09.080
[20]
Zhu, Y.H., Jiang, S.Q., Zhao, D.D., Cheng, G.J., Zhang, H.W. and Lai, W.E. (2013) Effects of Electropulsing on Microstructure and Conductivity of Nanofilms of Zn-Al Alloys. Applied Physics A, 111, 1241-1245.
http://dx.doi.org/10.1007/s00339-012-7396-2
[21]
Zhu, Y.H., Jiang, J., Xiao, Y.K., Luk, C.M. and Lai, W.E. (2013) Electropulsing Induced Microstructure Evolution and Its Effect on Electrical Conductivity of (Bi0.25Sb0.75)2Te3 Thin Films. Scripta Materialia, 69, 219-222.
http://dx.doi.org/10.1016/j.scriptamat.2013.03.032
[22]
Zhu, Y.H., To, S., Lee, W.B., Liu, X.M., Jiang, Y.B. and Tang, G.Y. (2009) Electropulsing Induced Phase Transformation in a Zn-Al Based Alloy. Journal of Materials Research, 24, 2661-2669.
http://dx.doi.org/10.1557/jmr.2009.0300
[23]
Zhang, D., To, S., Zhu, Y.H., Wang, H. and Tang, G.Y. (2012) Static Electropulsing Induced Microstrcutural Changes and Their Effects on Ultra-Precision Machining of a Cold-Rolled Alloy AZ91. Metallurgical and Materials Transactions A, 43, 1341-1346. http://dx.doi.org/10.1007/s11661-011-0955-x
[24]
Jiang, Y.B., Tang, G.Y., Shek, C.H., Zhu, Y.H. and Xu, Z.H. (2009) On the Thermodynamics and Kinetics of Electropulsing Induced Dissolution of β-Mg17Al12 Phase in an Aged Mg-9Al-1Zn Alloy. Acta Materialia, 57, 4797-4808.
http://dx.doi.org/10.1016/j.actamat.2009.06.044
[25]
Hu, G.L., Zhu, Y.H., Shek, C.H. and Tang, G.Y. (2011) Electropulsing-Induced G-Texture Evolution in a Deformed Fe-3%Si Alloy Strip. Journal of Materials Research, 26, 917-922. http://dx.doi.org/10.1557/jmr.2010.101
[26]
Zhu, Y.H., To, S., Liu, X.M., Jiang, Y.B. and Hu, G.L. (2011) Effect of Static Electropulsing on Microstructure and Elongation of a Zn-Al Alloy (ZA22). Metallurgical and Materials Transactions A, 42, 1933-1940.
http://dx.doi.org/10.1007/s11661-010-0591-x
[27]
Zhu, Y.H., To, S., Liu, X.M., Hu, G.L. and Xu, Q. (2011) Static Electropulsing Induced Phase Transformations in Cold Deformed ZA27 Alloy. Journal of Materials Research, 26, 1696-1701. http://dx.doi.org/10.1557/jmr.2011.185
[28]
Zhu, Y.H., To, S. and Liu, X.M. (2012) Influence of Spinodal Decomposition on Plastic Behavior of Dynamic Electropulsing Treated ZA22 Alloy. Materials Transactions, 53, 1363-1370.
http://dx.doi.org/10.2320/matertrans.M2012024
[29]
Jaeger, R.C. (2001) Introduction to Microelectronic Fabrication. Prentice Hall, Upper Saddle River, 81-88.
[30]
Zhu, Y.H., Chung, C.Y. and Lee, W.B. (2004) Nanophase Decomposition in Eutectoid Zn-Al Based Alloy Films. Materials Science and Engineering: A, 374, 145-152. http://dx.doi.org/10.1016/j.msea.2004.01.038
[31]
Conrad, H. and Sprencher, A.F. (2009) The Electroplastic Effect in Metals. Dislocation in Solid. Elsvier, Amstterdam, 497.
[32]
Sprecher, A.F., Mamnna, S.L. and Conrad, H. (1986) On the Mechanisms for the Electroplastic Effect in Metals. Acta Metallurgica, 34, 1145-1162. http://dx.doi.org/10.1016/0001-6160(86)90001-5
[33]
Hao, T., Tanimoto, H. and Mizubayashi, H. (2005) Transformation to Nanocrystallites in Amorphous Alloys Induced by Resonant Electropulsing. Materials Transactions, 46, 2898-2930. http://dx.doi.org/10.2320/matertrans.46.2898
[34]
Gumbsch, P. and Gao, H.J. (1998) Dislocations Faster than the Speed of Sound. Science, 283, 965-968.
http://dx.doi.org/10.1126/science.283.5404.965
[35]
Hu, G.L., Tang, G.Y., Zhu, Y.H. and Shek, C.H. (2011) Electropulsing Induced Texture Evolution in the Recrystallization of Fe-3%Si Alloy Strip. Metallurgical and Materials Transactions A, 42, 3484-3490.
http://dx.doi.org/10.1007/s11661-011-0770-4
[36]
Miao, D.G., Jiang, S.X., Jiang, S.M. and Chen, Z.M. (2014) Effect of Heat Treatment on Infrared Property of Al Doped ZnO Films. Solar Energy Materials & Solar Cells, 127, 163-168.
http://dx.doi.org/10.1016/j.solmat.2014.04.030
[37]
Kuo, S., et al. (2006) Effects of Dopping Concentration and Annealing Temperature on Properties of Highly-Oriented Al-Doped ZnO Films. Journal of Crystal Growth, 287, 78-84. http://dx.doi.org/10.1016/j.jcrysgro.2005.10.047
[38]
Wimmer, M., Ruske, F., Scherf, S. and Rech, B. (2012) Improving the Electrical and Optical Properties of DC-Sput-tered ZnO:Al by Thermal Post Deposition Treatment. Thin Solid Films, 520, 4203-4207.
http://dx.doi.org/10.1016/j.tsf.2011.04.102
[39]
Zhu, Y.H. (2004) General Rule of Phase Decomposition of Zn-Al Based Alloys (II)—On Effects of External Stress on Phase Transformation (Overview). Materials Transactions, 45, 3083-3097.
http://dx.doi.org/10.2320/matertrans.45.3083
[40]
Zhu, Y.H., Lee, W.B. and To, S. (2003) Use of EBSD to Study Stress Induced Microstructural Changes in Zn-Al Based Alloy. Materials Science and Engineering: A, 348, 6-14. http://dx.doi.org/10.1016/S0921-5093(02)00252-6
