Two hydrogen-related defects in ZnO are identified by a combination of local vibrational mode spectroscopy and first-principles theory. The H-I center consists of one hydrogen atom at the bond-center site oriented along the c axis of the crystal. The H-II center contains two inequivalent hydrogen atoms primarily bound to oxygen atoms. The polarized absorption data allow us to identify H-II as a zinc vacancy having two hydrogen atoms.

Atomic resolution in transmission electron microscopy of thin and light-atom materials requires a rigorous reduction of the beam energy to reduce knockon damage. However, at the same time, the chromatic aberration deteriorates the resolution of the TEM image dramatically. Within the framework of the SALVE project, we introduce a newly developed $C_c/C_s$ corrector that is capable of correcting both the chromatic and the spherical aberration in the range of accelerating voltages from 20 to 80 kV. The corrector allows correcting axial aberrations up to fifth order as well as the dominating off-axial aberrations. Over the entire voltage range, optimum phase-contrast imaging conditions for weak signals from light atoms can be adjusted for an optical aperture of at least 55 mrad. The information transfer within this aperture is no longer limited by chromatic aberrations. We demonstrate the performance of the microscope using the examples of 30 kV phase-contrast TEM images of graphene and molybdenum disulfide, showing unprecedented contrast and resolution that matches image calculations.