Surface modification and deuterium retention of tungsten films under low energy deuterium ion irradiation

Abstract

Tungsten (W) films prepared by radio frequency (RF) magnetron sputtering at 1 Pa, 3 Pa, and 5 Pa were irradiated by low-energy (50 eV, 300 eV, and 600 eV) deuterium ions at room temperature (RT), 573 K and 873 K, with fluences ranging from 3.2 × 1022/m2 to 9.0 × 1022/m2. Exfoliation was observed in the W film deposited at 1 Pa after irradiation of RT, 3.2 × 1022/m2, 300 eV D+. W films prepared at 5 Pa suffered the irradiation of different fluences, energies, and temperatures without degradation. SEM showed granules appearing and a rougher surface after irradiation. Irradiation energy, fluence and temperature played critical roles in D retention of tungsten. ERD showed D retention initiated and increased with increasing energies from 50 eV to 600 eV and with increasing fluences from 3.2 × 1022/m2 to 9.0 × 1022/m2, whereas nearly no D retention occurred in the W film irradiated at 873 K.