Uniform Multilayer Graphene for Space Plasma Instrumentation
With plasma being the most common state of matter in the universe, it is no wonder why astronomers and the like are very interested in studying plasma. Scientists have sent many probes, shuttles, and spacecraft into our solar system with the purpose to study the plasma surrounding or composing the celestial bodies around Earth, including the plasma giant we call the Sun. To collect data and information from these celestial bodies, spacecraft are equipped with space plasma instruments which detect plasma or ions. One of the common components of these instruments is the use of carbon as a foil to take advantage of two properties which occur between foils and particles: charge conversion and secondary electron emission. Carbon foils have been used for decades in space plasma instrumentation to detect ions and energetic neutral atoms and have allowed researchers to obtain a better understanding of space plasma and have resulted in many scientific advancements. However, the use of these foils produces adverse effects such as angular scattering and energy straggling during detection phases which inhibits the performance of these instruments. These issues are correlated with incident angle, energy, mass of the projectile and foil thickness. With the discovery of graphene, studies have indicated that graphene foils are a promising replacement for carbon foils due to their incredible strength and extreme thinness. These results have shown that graphene foils have similar charge state distributions to carbon foils, decrease angular scattering, and lower average energy loss. Such results indicate that graphene may soon replace carbon foils and create new opportunities for space research. However, due to the current transfer processes during the manufacture of graphene foils, most commonly using poly(methyl methacrylate) (PMMA), impurities present on the foils impede the detection process in space plasma instruments. This is due to the difficulties in removing the transfer layer, leaving a residual film. This research will focus on current transfer processes and the production of uniform multilayer graphene for its implementation in space plasma instruments. Producing a more uniform multilayer graphene will reduce the potential for contamination and defects by allowing for a transfer process which does not require a transfer layer.
Graphene, Plasma, CVD, Multilayer, Uniform
LePere, M. (2020). <i>Uniform multilayer graphene for space plasma instrumentation</i> (Unpublished thesis). Texas State University, San Marcos, Texas.