Environmental life cycle assessment of a carbon nanotube-enabled semiconductor device

Carbon nanotubes (CNTs) demonstrate great promise in a variety of electronic applications due to their unique mechanical, thermal, and electrical properties. Although commercialization of CNT-enabled products is increasing, there remains a significant lack of information regarding the health effects and environmental impacts of CNTs as well as how the addition of CNTs may affect the environmental profile of products. Given these uncertainties, it is useful to consider the life cycle environmental impacts of a CNT-enabled product to discover and potentially prevent adverse effects through improved design. This study evaluates the potential application of CNT switches to current cellular phone flash memory. Life cycle assessment (LCA) methodology is used to track the environmental impacts of a developmental nonvolatile bistable electromechanical CNT switch through its fabrication, expected use, and end-of-life. Results are reported for environmental impact categories including airborne inorganics, land use, and fossil fuels, with the largest contributions from gold refining processes and electricity generation. First-order predictions made for the use and end-of-life (EOL) stages indicate that the CNT switch could provide potential improvements to reduce environmental burden during use, although CNT release could occur through existing EOL processes.