Abstract: A field electron emission material comprises an electrically conductive substrate and, disposed thereon, electrically conductive particles embedded in, formed in, or coated by a layer of inorganic electrically insulating material. A first thickness material is defined between the particle and the environment in which the material is disposed. The dimension of each particle between the first and second thicknesses is significantly greater than each thickness. Upon application of a sufficient electric field, each thickness provides a conducting channel, to afford electron emission from the particles By use of an inorganic insulating material, surprisingly good stability and performance have been obtained. The particles can be relatively small, such that the electron emitting material can be applied to the substrate quite cheaply by a variety of methods, including printing. The material can be used in a variety of devices, including display and illuminating devices.