Low-Dimensional Materials
Thin Film Stress
Thin films and coatings are used in applications ranging from hard surfaces on cutting tools to interconnects for microelectronic devices and reflective coatings for optics. However, residual stress in these films provides a substantial driving force for film failures through bulging, cracking and delamination. To date control of residual stress in thin films is typically a "trial and error" process achieved through varying the deposition conditions (e.g. growth rate, pressure, and/or substrate temperature). Professor Thompson's group is interested in how different processing parameters individually and collectively contribute to the stress state and microstructural development of thin films. Of specific interest is how the addition of solutes influences the stress response and microstructure of the films. Through coupling in situ stress measurements using laser interferometry and post mortem microstructural characterization Professor Thompson seeks to develop an understanding of the complex kinetic and microstructural behavior of stress evolution to ultimately predict stress conditions.
Highlighted Papers:
T. Kaub and G.B. Thompson "Ti segregation in regulating the stress and microstructure evolution in W-Ti nanocrystalline film" Journal of Applied Physics 122 (2017) 085301
X. Zhou, T. Kaub, R. Martens, and G.B. Thompson "Influence of Fe(Cr) Miscibility on Thin Film Grain Size and Stress" Thin Solid Films 612 (2016) 29-35
B. Fu and G.B. Thompson “Compositional dependent thin film stress states” Journal of Applied Physics 108 (2010) pp. 043506-1 to 6.
B. Fu, W. An, C.H. Turner and GB Thompson “In situ thin film growth stresses during chemical ordering” Physical Review Letters 105 (2010) 096101
X. Zhou, T. Kaub, R. Martens, and G.B. Thompson "Influence of Fe(Cr) Miscibility on Thin Film Grain Size and Stress" Thin Solid Films 612 (2016) 29-35
B. Fu and G.B. Thompson “Compositional dependent thin film stress states” Journal of Applied Physics 108 (2010) pp. 043506-1 to 6.
B. Fu, W. An, C.H. Turner and GB Thompson “In situ thin film growth stresses during chemical ordering” Physical Review Letters 105 (2010) 096101
Nanoscale Stability in Low-Dimensional Materials
As the physical dimensions of materials are reduced into the nanometer regime, phase and chemical stability can be altered. With these changes, the associated properties of the materials are also changed. By understanding the governing behavior of these transformations and stability conditions, means to manipulate and tailor property responses can be achieved. Professor Thompson's group aims at understanding the growth of thin films and how phase stability, nano(micro)structure, and mechanical properties evolve. In these efforts, his group explores multilayered and alloy films as case studies. Particular emphasis is given to interfaces, which play a dominate role in controlling the chemical partitioning and crystal stability of materials. He has a concerted effort in the application of in situ laser interferometry to measure the stress responses of growing these types of films. The mechanical response of films during growth can be used to infer atomic mobility on or near these types of interfaces. Coupling analytical microscopy and computational materials science, Professor Thompson's research aims at developing a comprehensive understanding of how interfacial structure regulates and controls stability in materials in the nanoscale regime.
Highlighted Papers:
J.G. Brons, J.A Hardwick, H.A. Padilla II, K. Hatter, G.B Thompson and B.L. Boyce “The role of copper twin boundaries in cryogenic indentation-induced grain growth” Materials Science & Engineering A 592 (2014) 182-188
J.G. Brons, and G.B. Thompson “A comparison of grain boundary evolution during grain growth in fcc metals” Acta Materialia 61 (2013) 3936-3944
Yuki Inaba, Iulica Zana, Caleb Swartz, Yukiko Kubota, Tim Klemmer, J. W. Harrell and Gregory B. Thompson “Time-Temperature-Transformation Measurements of FePt Thin Films in the Millisecond Regime using Pulse Laser Processing” Journal of Applied Physics, 108, (2010) 103907
C. Srivastva, DE Nikles and GB Thompson “Tailoring nucleation and growth conditions for narrow compositional distributions in colloidal synthesized FePt nanoparticles” Journal of Applied Physics 104 (2008) 104314
J.G. Brons, and G.B. Thompson “A comparison of grain boundary evolution during grain growth in fcc metals” Acta Materialia 61 (2013) 3936-3944
Yuki Inaba, Iulica Zana, Caleb Swartz, Yukiko Kubota, Tim Klemmer, J. W. Harrell and Gregory B. Thompson “Time-Temperature-Transformation Measurements of FePt Thin Films in the Millisecond Regime using Pulse Laser Processing” Journal of Applied Physics, 108, (2010) 103907
C. Srivastva, DE Nikles and GB Thompson “Tailoring nucleation and growth conditions for narrow compositional distributions in colloidal synthesized FePt nanoparticles” Journal of Applied Physics 104 (2008) 104314