The interaction of hydrogen (H) with lithium (Li) and zinc vacancies (VZn) in hydrothermally grown n-type zinc oxide (ZnO) has been investigated by positron annihilation spectroscopy (PAS) and secondary ion mass spectrometry. Li on Zn-site (LiZn) is found to be the dominant trap for migrating H atoms, while the trapping efficiency of VZn is considerably smaller. After hydrogenation, where the LiZn acceptor is passivated via formation of neutral LiZn-H pairs, VZn occurs as the prime PAS signature and with a concentration similar to that observed in nonhydrogenated Li-poor samples. Despite a low efficiency as an H trap, the apparent concentration of VZn in Li-poor samples decreases after hydrogenation, as detected by PAS, and evidence for formation of the neutral VZnH2 complex is presented.
Johansen, K. M., Zubiaga, A., Tuomisto, F., Monakhov, E. V., Kuznetsov, A. Y., & Svensson, B. G. (2011). H passivation of Li on Zn-site in ZnO: Positron annihilation spectroscopy and secondary ion mass spectrometry. Physical Review B, 84(11), 1-4. . https://doi.org/10.1103/PhysRevB.84.115203