Optimization of Multiwalled Carbon Nanotube Photon Absorbers for Mid- and Far-Infrared Telescopes
- Paper number
IAC-11,B1,3,13,x11163
- Author
Mr. John Rigueur, Vanderbilt University, United States
- Coauthor
Dr. Stephanie Getty, National Aeronautics and Space Administration (NASA), United States
- Coauthor
Dr. John Hagopian, National Aeronautics and Space Administration (NASA), United States
- Coauthor
Mr. Gregory Hidrobo, National Aeronautics and Space Administration (NASA), United States
- Coauthor
Mr. Manuel Quijada, National Aeronautics and Space Administration (NASA), United States
- Year
2011
- Abstract
The purpose of our investigation is to optimize the growth of vertically aligned catalyst assisted chemical vapor deposition grown carbon nanotubes for use as a photon absorber in mid- to far-infrared applications. Improvement of the height and density of the carbon nanotubes will effectively increase the films absorptivity, bringing this material closer to an ideal absorber. NASA is currently exploring the use of this technology towards improving the observational data collected for future earth and space science missions. Detrimental to these scientific instruments is the excess stray light that scatters on interior telescope surfaces and contaminates gathered data, thereby reducing the performance of observational instruments. In order to control this undesired effect, low-reflectance surface treatments are implemented in structural instrument designs. Z306 black paint is traditionally used to absorb stray photons, but advanced absorbers that employ films of multi-walled carbon nanotubes (MWCNTs) have been shown [Hagopian et al., Proceedings of the SPIE 7761 (2010)] to provide an order of magnitude improvement over current surface treatments in the UV-visible-near infrared wavelengths of 300 nanometers to 1.9 microns. In this work, we report on a method of optimization for nanotube films to extend the order of magnitude improvement to spectral wavelengths greater than 2 micrometers using catalyst assisted chemical vapor deposition (CVD). To this end, we varied the thickness of the iron catalyst layer and deposition conditions to optimize the MWCNT length and film density for efficient absorption of longer wavelength photons. Scanning electron microscopy is used to characterize film density and MWCNT height, and hemispherical reflectance measurements are used to quantify performance of the absorptive films. Driven by demands for greater robustness and low structural mass as required by spaceflight applications, we will report on the use of lightweight titanium substrates and adhesion enhancements using an alumina layer underneath the iron catalyst. Quantitative measurements of film adhesion using lateral force microscopy will be discussed.
- Abstract document
- Manuscript document
(absent)