The Mechanical Behavior of Novel Periodic Cellular Structures based on TPMS, Platonic and Archimedean Lattices

  • Sumaya Y. Altamimi

Student thesis: Doctoral Thesis

Abstract

Graphene, serving as an ideal two-dimensional material platform, exhibits extraordinary electrical, optical, thermal and mechanical properties. The growth of graphene at low temperature has been an outstanding goal for the community to avoid the drawbacks of the transfer process and directly grow in semiconductors that maybe affected by the high temperature growth. This thesis addresses the potential of growing graphene directly on semiconductors at low temperatures using a conventional thermal CVD and PECVD. For the thermal CVD the low temperature growth is achieved by expanding the capability of the CVD system in two ways: one by reducing the temperature of the CVD chamber to the lowest possible point that allows decomposition of the gas. The second is by moving the substrate along the horizontal line of the CVD chamber taking advantage of the thermal variation of the system. For the first procedure, we grow graphene on copper at a descending temperature from 1000 OC to 700 OC. Then we follow a similar bath to grow the graphene on Ge which is an appropriate analogue to Cu due to the low solubility of carbon in both materials. In the second procedure, we take advantage of the fact that the CVD furnace covers the middle part of the CVD chamber allowing the temperature to vary across the horizontal line creating two regions: high temperature zone (HT), and low temperature zone (LT). We study the temperature variation across the CVD chamber while the CVD furnace temperature is fixed at 1000OC to find an optimum spot where temperature and energy are most suitable for graphene growth. We always Start with cupper to demonstrate the validity of this procedure and demonstrate the potential of growing graphene directly on GAAs. These methods resulted in the growth of nonuniform graphene layer on germanium at temperature of 800℃ and gallium arsenide substrates at temperature of 500 ℃. For PECVD, we report the direct growth of large-area, uniform Vertically aligned graphene nanosheet arrays (VAGNAs) terminated with a high-quality single-layer graphene sheet at a low temperature of 625℃ on Germanium substrate.
Date of AwardDec 2020
Original languageAmerican English
SupervisorRashid Abu Al Rub (Supervisor)

Keywords

  • Cellular Solids
  • Triply Periodic Minimal Surfaces; Strut-based Structures
  • TPMS-derived Lattices
  • Platonic based Lattices
  • Archimedean based Lattices
  • Additive Manufacturing
  • Finite Element Analysis
  • Uniaxial Compression Test.

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