Controlled growth and field-emission properties of cobalt oxide nanowalls

Vertically oriented single-crystalline CO3O4 nanowalls (see Figure) have been successfully fabricated by directly heating Co foil in air using a hot plate. The morphologies of the Co3O4 nanowalls can be controlled by varying the growth temperature and time. The Co3O4 nanowalls show promising field-emission performance that is comparable to many other nanomaterials.