W18O49 nanowires were synthesized by thermal evaporation, and the effects of X-ray irradiation on their crystalline structure, chemical composition, and field emission properties were systematically investigated. High-energy X-ray irradiation created nanoprotrusions on the surface of W18O49 nanowires and introduced crystalline slipping in the lattice. X-ray photoelectron spectroscopy results showed that the content of lattice oxygen increased and nitrogen was incorporated into the W18O49 nanowires after X-ray irradiation. Nevertheless, a stable and high current emission still could be obtained from the W18O49 nanowires after X-ray irradiation, with a slight increase in the threshold field from 6.4 to 7.9 MV m−1. The mechanism of the change in crystalline structure, chemical composition, and field emission performance of W18O49 nanowires induced by X-ray irradiation is discussed.
