Abstract: A field emitter device for selective emission of an electron and/or ion beam comprising a substrate member having an array of field emitter elements thereon, in which the field emitter elements and/or substrate member have a varied conformation producing a beam of appropriate focused and/or directional character. Also disclosed is a display article for producing an output in response to impingement of electron beams thereon, comprising a substrate member on which is disposed an array of phosphor elements, with a diamond-like film coated on the phosphor elements to maintain the phosphor elements in position on the substrate member. Also disclosed is a field emission apparatus comprising such field emitter device and display article, such as a flat panel display.