High-efficiency field emission from pressed nickel foam flat graphene-vertical graphene hybrids

Vertical graphene (VG) was prepared on flat graphene (FG) coated pressed Ni foams by using plasma enhanced chemical vapor deposition. The VG is typical few-layer graphene and is rich in defects. The field emission performance of Ni-FG-VG hybrids with optimal morphology is found to outperform that of VG prepared on pristine Ni foams and Si wafers. It has a low turn-on electric field of 2.03 Wpm and a large maximum emission current density (J(max)) of 5.91 mA/cm(2) and also exhibits excellent field emission stability at similar to 50% and similar to 75% j(max) over a period of 30 h. (C) 2016 Elsevier B.V. All rights reserved.