Field electron emission materials and devices

To create a field electron emission material, there is printed upon a substrate (1501) an ink (1503) comprising a major component of fluid vehicle; a first minor component of electrically insulating material, either on its own or provided within a precursor therefor; and a second minor component of electrically conductive particles (1504). The printed ink is then treated to expel the major component and create the field electron emission material from the minor components on the substrate. The electrically conductive particles may be omitted, to print a solid, electrically insulating layer in a field emission device.