Synthesis of octahedral ZnGa2O4 particles and their field-emission properties

ZnGa2O4 particles that are regular octahedra in shape and uniform in size were synthesized on Si substrates via catalyst-free chemical vapour deposition. The surfaces of the octahedra are bounded by {1 1 1} facets. A model based on surface energy dependent growth rate is proposed for interpreting the appearance of the octahedra. The field-emission (FE) properties of the octahedral particles were measured. The turn-on field required for producing an emission current density of 0.1 mu Acm(-2) is 11V mu m(-1), and the field enhancement factor (beta) is about 1256, which is high enough for various FE applications.