Interaction of hydrogen with Zr(0001) at room temperature

Abstract

The interaction of hydrogen with a Zr(0001) surface at room temperature has been investigated by using 2H(3He,p)4He nuclear reaction analysis (NRA), dynamic secondary ion mass spectroscopy, static secondary ion mass spectroscopy, and Auger electron spectroscopy. The initial sticking coefficient (for D) obtained from the absolute deuterium coverage measured by NRA was found to be 0.38±0.16 which is higher than a previously published value by about four orders of magnitude. Secondary ion mass spectroscopy H+ integrated intensities were converted to hydrogen concentration by calibration using NRA. The sticking coefficient for H2 appears to be very similar to that for D2. It was found that the hydrogen atoms appear to stay at the surface until the surface concentration saturates at 0.77 monolayer (4 L exposure). Upon further exposure the hydrogen penetrates through the surface. The valence-band-related Auger transitions show a small but discernible change upon exposure to greater than 2 L hydrogen. This, as well as changes in the low-energy electron diffraction pattern, indicates the formation of hydride in the early stages of exposure. An uptake model was proposed, from which a good agreement for sticking coefficient with NRA results was obtained.