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

• Vertical graphene was prepared on flat graphene coated pressed Ni foams.
• The VG is typical few layer graphene.
• The pressed Ni–FG–VG hybrids have low operation electric fields.
• The pressed Ni–FG–VG hybrids present excellent field emission stability.

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 V/μm and a large maximum emission current density (Jmax) of 5.91 mA/cm2 and also exhibits excellent field emission stability at ~50% and ~75% Jmax over a period of 30 h.

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