University of Connecticut OpenCommons@UConn Doctoral Dissertations University of Connecticut Graduate School 8-6-2013 Physical Vapor Deposition of Nanorods from Science to Technology Stephen P. Stagon Graduate Student, [email protected] Follow this and additional works at: https://opencommons.uconn.edu/dissertations Recommended Citation Stagon, Stephen P., "Physical Vapor Deposition of Nanorods from Science to Technology" (2013). Doctoral Dissertations. 189. https://opencommons.uconn.edu/dissertations/189 Physical Vapor Deposition of Nanorods from Science to Technology Stephen P. Stagon, PhD University of Connecticut, 2013 The transition from nanoscience to nanotechnology is dependent on a level of scientific maturity. After over 6 decades of nanoscience, this level of maturity has only recently been approached. In this work we first present the current state of nanoscience and nanotechnology in the context of nanofabrication using solution syntheses, chemical vapor deposition and physical vapor deposition. To lay the groundwork for scientific investigation into these three, we choose physical vapor deposition as the prototype due to its high purity and elimination of interfering variables. We then present the emergence of a new level of scientific understanding of nanorod growth from physical vapor deposition, realized through the synergy of experiments, theory and simulation, and of fast diffusion on these nanorod surfaces. Throughout, we discuss the pioneering engineering advances in physical vapor deposition that lead to this realization. Further, as a true technological impact, this new level of scientific understanding has enabled the realization of room temperature metallic bonding and sealing. Moving beyond low temperature bonding, we discuss the realization of several new morphologies which may offer even more real technological impact. We close with a discussion on the importance of completing the scientific understanding of nanoscale growth from all three mechanisms- solution, chemical vapor and physical vapor- and the technologies that are primed for this impact. Physical Vapor Deposition of Nanorods from Science to Technology Stephen Peter Stagon B.S., University of Connecticut, 2009 A Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy at the University of Connecticut 2013 Copyright by Stephen Peter Stagon 2013 APPROVAL PAGE Doctor of Philosophy Dissertation Physical Vapor Deposition of Nanorods from Science to Technology Presented by Stephen Peter Stagon, B.S. Mechanical Engineering Major Advisor Dr. Hanchen Huang Associate Advisor Dr. Tai-Hsi Fan Associate Advisor Dr. Radenka Maric Associate Advisor Dr. Kevin Murphy Associate Advisor Dr. Ugur Pasaogullari University of Connecticut 2013 ACKNOWLEDGEMENTS I would like to begin by thanking my wonderful and patient wife Jennifer, my parents, my brother Matt, my family and my friends - your constant encouragement and frequent and persistent pressure where the only things that enabled me to have the perseverance to finish this work. I would also like to thank my counterparts and collaborators for their helpful conversation, both scientific and otherwise, and physical contributions to this work. First, without the technical guidance and encouragement of Pete Menard the experimental facilities would not have materialized. Without the technical assistance of Joe and Mark at UConn Technical Services the UHV vacuum chamber would not have held a vacuum of any level. The simulation and theoretical formulations found in this dissertation are the product of years of hard work from Dr. L.G. Zhou, Dr. Xiaobin Niu and Dr. Yongfeng Zhang who also offered me encouragement and guidance to navigate my graduate studies. I would like to thank my adviser for his years of positive support, critical analysis and freedom to pursue areas of my own interest and take a level of personal ownership that few attain. The freedom and support truly enabled me to find confidence in my skills and career that have translated to the rest of my life. Finally, I would like to thank my entire thesis committee for their valuable input and help in my academic career culminating in this dissertation which brings me deep pride and sense of accomplishment. Dr.’s Fan and Murphy, your classes in both undergraduate and graduate levels helped to shape me academically. Dr.’s Maric and Murphy, thank you for our valuable conversations over the past years, about both academics and work-life balance alike. Dr.’s Fan, Maric and Pasaogullari, thank you for our interesting scholarly collaborations which we will continue into the future. i TABLE OF CONTENTS I. Introduction ........................................................................................................................................... 1 1. What is nanotechnology and does it even matter? ............................................................................ 1 2. Review of PVD of nanostructures .................................................................................................... 4 3. Motivation for this study – Three clear challenges ......................................................................... 16 II. Bottom up Nanofabrication: Mechanisms and Instrumentation ......................................................... 18 1. Solution Synthesis ........................................................................................................................... 19 2. Chemical Vapor Deposition (CVD) ................................................................................................ 26 a. CVD Fabrication Overview ........................................................................................................ 27 b. The CVD Reactor ....................................................................................................................... 33 3. Physical Vapor Deposition (PVD) .................................................................................................. 36 4. The electron beam PVD system ...................................................................................................... 46 5. Materials Characterization on the Nanoscale .................................................................................. 51 III. Scientific State of Nanostructures from Physical Vapor Deposition .............................................. 64 1. Thermodynamic Crystal Growth Primer ......................................................................................... 64 2. Glancing and Oblique Angle Deposition in PVD ........................................................................... 69 IV. A New Scientific Contribution: The Smallest Metallic Nanorods from Physical Vapor Deposition 76 1. Anomoly of film porosity dependence on deposition rate .............................................................. 76 2. Emergence of a framework of nanorod growth (JOM) ................................................................... 85 3. The smallest nanorods from physical vapor deposition .................................................................. 88 V. Filling in the Framework of Nanorods from Physical Vapor Deposition ........................................... 96 1. FCC metal systems ( Pt, Ni, Al, Ag) ............................................................................................... 96 2. Engineering diffusion barriers – Low temperature growth ........................................................... 109 3. Non-FCC metals extension necessary in scientific understanding to meet up to fabrication knowledge (Cr, Co, Si) ......................................................................................................................... 120 VI. From Nanoscience to Nanotechnology ......................................................................................... 124 1. Low temperature metallic bonding ............................................................................................... 124 VII. Future Exploration and Conclusions ............................................................................................. 150 1. Scientific investigation .................................................................................................................. 150 2. Technology ................................................................................................................................... 153 Bibliography ............................................................................................................................................. 157 ii TABLE OF FIGURES Figure 1: Schematic of solution synthesis of metallic nanorods and nanoparticles. ................................... 20 Figure 2: Electrochemical growth of small nanorods with the template method top, and sonication method, bottom. .......................................................................................................................................... 23 Figure 3: Seeded solution synthesis of small Au nanorods. ........................................................................ 25 Figure 4: Schematic of CVD growth (top) with representative single zone temperature profile (bottom). 28 Figure 5: ZnO nanoflower grown from carbon catalyzed CVD. ................................................................ 30 Figure 6: The vapor liquid solid mechanism of nanowire growth. ............................................................. 32 Figure 7: In house