Enhanced field emission from self-assembled ZnO nanorods on graphene/Ni/Si substrates

Self-assembled ZnO nanorods/graphene field emission structures were fabricated by using a hydrothermal growth of nanorods on few layer graphene (FLG) substrates. The FLG patterned electrode was used to improve the contact resistance and to control the density and the area of field emission. This approach allows creation of high-performance field emission devices over a large area using an inexpensive low-temperature growth and FLG patterned substrates. The obtained ZnO NRs/FLG field emission structures operate at a low vacuum of 10−5 Torr and low turn-on electric field of 0.9 V/µm, demonstrating a high field enhancement factor β=5556.