Study of gas-based charge compensation in an open-cell environmental TEM by off-axis electron holography

Under electron bombardment, electrically insulating samples accumulate a net charge which can adversely affect measurements in electron microscopy. Here, we present a preliminary study on gas-based charge compensation in TEM quantified through off-axis electron holography. Based on the present data, it appears that the introduction of a gas flow reversibly reduces the degree of charge buildup and fluctuations on a dielectric sample. The use of gas may thus allow for the study of samples which would normally be strongly distorted, unstable, or damaged by the charging process; as well as further studies of the charging process itself. However, as the present results were obtained with low spatial resolution Lorentz optics and second-scale time resolutions, we caution that the effectiveness of gas-based charge compensation for high spatial and temporal resolutions is not yet demonstrated.