Radiation Degradation of Nanomaterials

Abstract

ABSTRACTWe have been developing a variety of nanomaterials for their use in power devices. An example of this is our use of both single wall carbon nanotubes and several varieties of semiconducting quantum dots (e.g., CuInS2, CdSe, InAs) for use in space solar cells. The ability of these materials to withstand the rigors of the space radiation environment will be essential for this intended application. In addition, we have also been developing both nanostructure III-V devices and radioluminescent quantum dots for use in radioisotope batteries. In this application these nanomaterials are subjected to an extremely high radiation level. Their degradation rate will be the key to determining the ultimate lifetime of these power supplies, which in principle can have an energy density that is orders of magnitude higher than any conventional battery chemistry. The nanomaterials included in this study were subjected to alpha particles fluences and the degradation in various properties were monitored using different analytical techniques. Specifically, the radioluminescence of the quantum dot intended for use in the radioisotope batteries was monitored as a function of fluence. In the case of the III-V quantum dots, their photoluminescent degradation as a function of fluence was measured in comparison to the bulk substrate on which the quantum dots were grown. Finally for the carbon nanotubes, relative intensities of the Raman peaks associated with their inherent vibrational modes was used to monitor the effects of the alpha radiation damage. Results on the radiation tolerance of these nanomaterials and its implication with regard to their ultimately utility in power devices are presented.