Temperature-dependent mean inner potential of polystyrene spheres measured using off-axis electron holography

Off-axis electron holography is used to measure the temperature dependence of the mean inner potential and electron-beam-induced charging effects in polystyrene spheres with diameters of between 230 and 600 nm from room temperature to 5.3 K. Integrating the model independent and line fitting simulation approaches, enabled by the high quality of the recorded holograms, it has been possible to disentangle the contribution the beam induced charge from that of the mean inner potential (MIP), finding that both quantities (at least for the smaller spheres) increase with decreasing temperature. In particular the MIP reaches a value of (6.48 ± 0.26) V at 5.3 K, corresponding to an increase of 16.8% ± 4.2%, with respect to the measurements carried at room temperature, giving the value (5.55 ± 0.07) V.