Two distinct isolated hydrogen defects are observed in crystalline Ge by in
situ infrared absorption spectroscopy. Implantation of protons into Ge at
cryogenic temperatures gives rise; to two intense ab: sorption lines at 745
and 1794 cm(-1). The lines originate from distinct defects, each of which
contains one H atom located on a [111] axis. The 1794-cm(-1) line is assign
ed to bond center H in the positive charge state, whereas the 745-cm(-1) li
ne is ascribed to negatively charged H located on a [111] axis close to the
tetrahedral site.