Dielectric treatments for carbon nanotube devices are provided. In one aspect, a method for forming a carbon nanotube-based device is provided. The method includes: providing at least one carbon nanotube disposed on a first dielectric; removing contaminants from surfaces of the first dielectric; and depositing a second dielectric onto the first dielectric and at least partially surrounding the at least one carbon nanotube. A carbon nanotube-based device is also provided.