The H-related defects in proton-implanted crystalline material were studied by means of infra-red spectroscopy. Absorption lines at 1979.5, 1992.6, 2014.9, 2024.8 and 2061.5/cm in hydrogenated samples were identified as being the Ge-H stretching modes of 3 distinct vacancy-H complexes.

Vacancy-Hydrogen Complexes in Group-IV Semiconductors M.Budde, B.Bech Nielsen, J.C.Keay, L.C.Feldman: Physica B, 1999, 273-274, 208-11