Improved field emission of CNTs on heated substrate for medical x-ray imaging application

For the next generation x-ray imaging system, small focal spot combined with fast switching electron emitter is desired to obtain high resolution images and minimize motion-induced blurring of images of moving organs such as the heart. Carbon nanotubes (CNTs) have the potential to be excellent emitters for novel x-ray imaging applications that overcome the limitations imposed by conventional thermal emitters. One of the challenges for achieving high emission current from CNT is the early breakdown of emitters due to the Joule heating of the CNT/substrate interface, field evaporation of CNTs and subsequent formation of ions leading to arcing. CNT emitters require emission stability and reproducibility.