Vacuum ultraviolet emission from microwave Ar-H2 plasmas

Vacuum ultraviolet emission from Ar-H2 wave driven microwave (2.45 GHz) plasmas operating at low pressures (0.1–1 mbar) has been investigated. The emitted spectra show the presence of the Ar resonance lines at 104.8 and 106.7 nm and of the Lyman-α,β atomic lines at 121.6 nm and 102.6 nm, respectively. The increase of the hydrogen amount in the mixture results in an abrupt increase of the Werner and Lyman molecular bands intensity. The Lyman-β intensity shows little changes in the range of 5%–30% of hydrogen in the mixture while the Lyman-α intensity tends to decrease as the percentage of hydrogen increases.