Selective epitaxial growth of CaNH and CaNH thin films by reactive magnetron sputtering under hydrogen partial pressure control

Chon, S.*; Fukutani, Katsuyuki; 8 of others*

Calcium compounds with N and H are promising catalysts for NH conversion, and their epitaxial thin films provide a platform to quantitatively understand the catalytic activities. Here we report the selective epitaxial growth of CaNH and CaNH thin films by controlling the hydrogen partial pressure () during reactive magnetron sputtering. We find that the hydrogen charge states can be tuned by : CaNH containing H is formed at Pa, while CaNH containing H is formed at Pa. In situ plasma emission spectroscopy reveals that the intensity of the Ca atomic emission (422 nm) decreases as increases, suggesting that Ca reacts with H and N to form CaNH at lower , whereas at higher , CaH is first formed on the target surface and then sputtered to produce CaNH. This study provides a novel route to control the hydrogen charge states in Ca-N-H epitaxial thin films.