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Investigation of Structural Characteristics of III-V Semiconductor Nanowires Grown by Molecular Beam Epitaxy Zhi Zhang Master of Chemical Engineering

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Investigation of Structural Characteristics of III-V Semiconductor Nanowires Grown by Molecular Beam Epitaxy Zhi Zhang Master of Chemical Engineering Investigation of Structural Characteristics of III-V Semiconductor Nanowires Grown by Molecular Beam Epitaxy Zhi Zhang Master of Chemical Engineering A thesis submitted for the degree of Doctor of Philosophy at The University of Queensland in 2015 School of Mechanical and Mining Engineering Abstract One-dimensional nanowires made of III-V semiconductors have attracted significant research interest in the recent decades due to their distinct physical and chemical properties that can potentially lead to a wide range of applications in nanoelectronics and optoelectronics. As a key class of III-V semiconductor nanowires, InAs nanowires have attracted special attention due to their narrow bandgap, relatively high electron mobility, and small electron effective mass, which made them a promising candidate for the applications in future optical and high- frequency electronic devices. One of the challenges in realizing these unique III-V nanowire properties in nanowire-based devices is to integrate nanowires on the nano-devices or chips with well-organized arrangement. To solve this issue, the epitaxial nanowire growth provides the uniqueness that well aligned nanowires can be grown on the chosen substrates, and by selecting substrates with particular orientations, specifically orientated nanowires can be grown. Au-assisted nanowire growth is one of the most common methods to grow epitaxial III-V nanowires via the vapor-liquid-solid (VLS) mechanism or vapor-solid-solid (VSS) mechanism. For III-V nanowires, one of the coherent problems is that the stacking faults and/or twin defects can easily be introduced in both wurtzite or zinc-blende structured nanowires due to the small energy differences between wurtzite and zinc-blende stacking sequences of their dense planes. For III-V nanowires to be practically useful, it is of significant importance to minimize the lattice defects in nanowires, and to control their crystal phase and structural quality. In this regard, in this thesis, we investigated the growth parameters on the growth behaviour, crystal phase and structural quality of III-V nanowires, particularly InAs and GaAs nanowires. By carefully tuning the growth parameters, we have successfully achieved the controlled growth of InAs and GaAs nanowires with defect-free wurtzite structure and/or zinc- blende structure. Meanwhile, although InAs nanowires have been grown by different growth techniques, such as metalorganic chemical vapor deposition (MOCVD) or chemical beam expitaxy (CBE), very few studies have been devoted to the growth of InAs nanowires in molecular beam epitaxy (MBE). In this thesis, we employed the MBE system to grow Au-catalysed InAs nanowires on the GaAs{111}B substrate. Our I extensive experiments have determined the relatively narrow V/III ratio window for the growth of InAs nanowires in MBE. Furthermore, by designing a two-V/III-ratio procedure, the pure defect-free zinc-blende structured InAs nanowires were achieved. II Declaration by author This thesis is composed of my original work, and contains no material previously published or written by another person except where due reference has been made in the text. I have clearly stated the contribution by others to jointly-authored works that I have included in my thesis. I have clearly stated the contribution of others to my thesis as a whole, including statistical assistance, survey design, data analysis, significant technical procedures, professional editorial advice, and any other original research work used or reported in my thesis. The content of my thesis is the result of work I have carried out since the commencement of my research higher degree candidature and does not include a substantial part of work that has been submitted to qualify for the award of any other degree or diploma in any university or other tertiary institution. I have clearly stated which parts of my thesis, if any, have been submitted to qualify for another award. I acknowledge that an electronic copy of my thesis must be lodged with the University Library and, subject to the policy and procedures of The University of Queensland, the thesis be made available for research and study in accordance with the Copyright Act 1968 unless a period of embargo has been approved by the Dean of the Graduate School. I acknowledge that copyright of all material contained in my thesis resides with the copyright holder(s) of that material. Where appropriate I have obtained copyright permission from the copyright holder to reproduce material in this thesis. III Publications during candidature Peer-reviewed papers 1. Zhang, Z.; Lu, Z.; Chen, P.; Lu, W.; Zou, J. Defect-Free Zinc-Blende Structured InAs Nanowires Realized by in-situ Two-V/III Ratio Growth in Molecular Beam Epitaxy. Nanoscale 2015, 7, 12592-12597. 2. Zhang, Z.; Shi, S.; Chen, P.; Lu, W.; Zou, J. Influence of Substrate Orientation on the Structural Quality of GaAs Nanowires in Molecular Beam Epitaxy. Nanotechnology 2015, 26, 255601. 3. Zhang, Z.; Lu, Z.; Chen, P.; Lu, W.; Zou, J. Controlling the Crystal Phase and Structural Quality of Epitaxial InAs Nanowires by Tuning V/III Ratio in Molecular Beam Epitaxy. Acta Mater. 2015, 92，25-32. 4. Zhang, Z.; Zheng, K.; Lu, Z.; Chen, P.; Lu, W.; Zou, J. Catalyst Orientation Induced Growth of Defect-Free Zinc-Blende Structured <00 ̅> InAs Nanowires. Nano Lett. 2015, 15, 876-882. 5. Zhang, Z.; Lu, Z.; Xu, H.; Chen, P.; Lu, W.; Zou, J. Structure and Quality Controlled Growth of InAs Nanowires through Catalyst Engineering. Nano Res. 2014, 7, 1640-1649. 6. Zhang, Z.; Lu, Z.; Chen, P.; Xu, H.; Guo, Y.; Liao, Z.; Shi, S.; Lu, W.; Zou, J. Quality of Epitaxial InAs Nanowires Controlled by Catalyst Size in Molecular Beam Epitaxy. Appl. Phys. Lett. 2013, 103, 073109. 7. Liao, Z; Chen, Z.; Lu, Z.; Xu, H.; Guo, Y.; Sun, W.; Zhang, Z.; Yang, L.; Chen, P.; Lu, W.; Zou, J. Au Impact on GaAs Epitaxial Growth on GaAs (111)B Substrates in Molecular Beam Epitaxy. Appl. Phys. Lett. 2013, 102, 063106. 8. Ye, D.; Wang, B.; Chen, Y.; Han, G.; Zhang, Z.; Hulicova-Jurcakova, D.; Zou, J.; Wang, L.; Understanding the Stepwise Capacity-increase of High Energy Low-Co Li-rich Cathode Materials for Lithium Ion Batteries. J. Mater. Chem. A 2014, 2, 18767-18774. 9. Lu, Z.; Zhang, Z.; Chen, P.; Shi, S.; Yao, L.; Zhou, C.; Zhou, X.; Zou, J.; Lu, W.; Bismuth-induced Phase Control of GaAs Nanowires Grown by Molecular Beam Epitaxy. Appl. Phys. Lett. 2014, 105, 162102. 10. Guo, N.; Hu, W.; Liao, L.; Yip, S.; Ho, J.; Miao, J.; Zhang, Z.; Zou, J.; Chen, X.; Lu, W.; Anomalous and Highly-efficient InAs Nanowire Phototransistors Based IV on Majority Carrier Transport at Room Temperature. Adv. Mater. 2014, 26, 8232-8232. 11. Shi, S.; Lu, Z.; Zhang, Z.; Zhou C.; Chen, P.; Zou, J.; Lu W.; Morphology and Microstructure of InAs Nanowires on GaAs Substrate Grown by Molecular Beam Epitaxy. Chin. Phys. Lett. 2014, 31 (9): 098101. 12. Shi, S.; Zhang, Z.; Lu, Z.; Shu, H.; Chen, P.; Li, N.; Zou, J.; Lu, W. Evolution of Morphology and Microstructure of GaAs/GaSb Nanowire Heterostructures. Nanoscale Res. Lett. 2015, 10, 108. 13. Shao, Y.; Wu, S.; Zhang, Z.; Zou, J.; Jiang, Z. Evolution of Thin Protecting Si- layer on Mn0.5Si0.5 Layer at Low Temperatures. Appl. Surf. Sci. 2015, 333, 54- 58. 14. Xu, B.; Wu, H.; Lin, C.; Wang, B.; Zhang, Z.; Zhao, X. Stabilization of Silicon Nanoparticles in Graphene Aerogel Framework for Lithium Ion Storage. RSC Adv. 2015, 5, 30624- 30630. 15. Zhang, X.; Shao, R.; Jin, L.; Wang, J.; Zheng, K.; Zhao, C.; Han, J.; Chen, B.; Sekiguchi, T.; Zhang, Z.; Zhang, Z.; Zou, J.; Song, B. Helical Growth of Aluminum Nitride: New Insights into its Growth Habit from Nanostructures to Single Crystals. Sci. Rep. 2015, 5, 10087. 16. Chen, H.; Wang, Q.; Lyu, M.; Zhang, Z.; Wang, L. Wavelength-Switchable Photocurrent in a Hybrid TiO2/Ag Nanocluster Photoelectrode. Chem. Commun. 2015, 51, 12072-12075. 17. Alaskar, Y.; Arafin, S.; Lin, Q.; Wickramaratne, D.; McKay, J.; Norman, A. G.; Zhang, Z.; Yao, L.; Ding, F.; Zou, J.; Goorsky, M.; Lake, R.; Zurbuchen, M.; Wang, K. Theoretical and Experimental Study of Highly Textured GaAs on Silicon Using a Graphene Buffer Layer. J. Cryst. Growth 2015, 425, 268-273. Conference abstracts 1. Zou, J.; Zhang, Z.; Xu, H.; Guo, Y.; Liao, Z.; Lu, Z.; Chen, P.; Lu, W.; Gao, Q.; Tan, H.; and Jagadish, C; Impact of Catalysts in the Epitaxial Growth of III-V Nanowires. ICONN2014-ACMM2. (Adelaide, 2014, Invited presentation) 2. Zhang, Z.; Lu, Z.; Chen, P.; Xu, H.; Guo, Y.; Liao, Z.; Shi, S.; Lu, W.; Zou, J.; Catalyst Size Dependent Structural Quality of InAs Nanowires Grown by Molecular Beam Epitaxy. ICAMP8. (Gold Coast, 2014.07, Oral presentation) V 3. Zhang, Z.; Lu, Z.; Xu, H.; Chen, P.; Lu, W.; Zou, J.; Effect of V/III Ratio on the Structural Quality of InAs Nanowires. COMMAD. (Perth, 2014.12, Oral presentation) 4. Zhang, Z.; Lu, Z.; Xu, H.; Chen, P.; Lu, W.; Zou, J. Effect of V/III Ratio on the Structural Quality of InAs Nanowires. IEEE.2014 Conference on Optoelectronic and Microelectronic Materials & Devices 2014, 24-26. (DOI: 10.1109/commad.2014.7038642) VI Publications included in this thesis Zhang, Z.; Lu, Z.; Chen, P.; Xu, H.; Guo, Y.; Liao, Z.; Shi, S.; Lu, W.; Zou, J. Quality of Epitaxial InAs Nanowires Controlled by Catalyst Size in Molecular Beam Epitaxy. Appl. Phys. Lett. 2013, 103, 073109. – incorporated as Chapter 4. Contributor Statement of contribution Zhi Zhang (Candidate) Design the experiments (70%) Carried out characterization (80%) Carried out data analysis (70%) Prepared the paper (60%) Zhenyu Lu Carried out nanowire growth (70%) Pingping Chen Carried out nanowire growth (20%) Supervised the project (10%) Prepared the paper (5%) Hongyi Xu Carried out characterization (10%) Yanan Guo Carried out characterization (5%) Zhiming Liao Carried out characterization (5%) Suixing Shi Carried out nanowire growth (10%) Wei Lu Supervised the project (10%) Prepared the paper (5%) Jin Zou Design the experiments (30%) Carried out data analysis (30%) Supervised the project (80%) Prepared the paper (30%) VII Zhang, Z.; Lu, Z.; Xu, H.; Chen, P.; Lu, W.; Zou, J.
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