Changes in morphology and field emission property of nano-tendril bundles after high temperature annealing

•Helium plasma with additional neon formed nano-tendril bundles.•Thermal response of nano-tendril bundles (NTB) was investigated up to 1673 K.•Sharp tips disappeared and fiber radius of NTB increased significantly around 1573 K.•Field emission from nano-tendril bundles decreased after the thermal treatment.•The thermal treatment significantly decreased the probability to ignite arcing.