W nano-fuzzes: A metastable state formed due to large-flux He+ irradiation at an elevated temperature

W nano-fuzzes have been formed due to the large-flux and low-energy (200eV) He+ irradiation at W surface temperature of 1480 °C. Microscopic evolution of W nano-fuzzes during annealing or low-energy (200 eV) He+ bombardments has been observed using scanning electron microscopy and thermal desorption spectroscopy. Our measurements show that both annealing and He+ bombardments can significantly alter the structure of W nano-fuzzes. W nano-fuzzes are thermally unstable due to the He release during annealing, and they are easily sputtered during He+ bombardments. The current study shows that W nano-fuzzes act as a metastable state during low-energy and large-flux He+ irradiation at an elevated temperature.