Abstract: By uniformly forming an indefinite number of microscopic acicular crystals on a surface of a silicon substrate so as to be perpendicular to the surface of the substrate by plasma CVD method using a catalyst, it is possible to reliably, homogeneously and massively form an ultramicroscopic acicular silicon crystal having a substantial cone shape tapered so as to have a radius of curvature of not less than 1 nm to no more than 20 nm at its tip end and having a diameter of bottom surface of not less than 10 nm, and a height equivalent to or more than the diameter of bottom surface, at a desired location.

Abstract: The principal objects of the invention is to provide diamond fine particles with a surface nature so improved as to form a stable, uniform suspension or dispersion in a common medium such as water and alcohol. Another object is to provide an effective technique for producing hydrophilic diamond fine particles by chemically modifying the particle surface nature, while removing at the same time contaminants and foreign materials which coexist with the diamond. In the invention, diamond particles are treated by boiling in the treatment fluid of sulfuric acid solution, which is in particular of concentrated or fuming nature, at a temperature more than 200° C., which is preferably 250° C. or more.

Abstract: The present invention provides an electron emitting device for efficiently emitting electron beams by applying a forward bias to an MIS, pn, and a pin structure using a diamond layer so as to supply electrons from an electron supply layer to a p-type diamond layer. Furthermore, the present invention provides a method for easily and efficiently performing important production processes for producing a highly efficient electron emitting device having a diamond layer and controlling a surface state of the diamond layer. A multi-layer structure including an electrode layer, an electron supply layer and a diamond layer is used as the structure thereof. Alternatively, the electron affinity state of the surface of the diamond layer is arbitrarily controlled by a method such as ultraviolet ray irradiation.