Charging effect on work function measurements of lithium ceramics under irradiation

The lithium ceramics Li2O, LiAlO2 and Li4SiO4 were studied under ion or electron beam irradiation using a Kelvin probe that measures the change in work function of the materials. Surface charging was observed to greatly influence the probe output, which can be explained qualitatively by employing a model of the polarization effect in insulating ceramics due to free charges on the surface. It was found that the insulating ceramics could not be studied properly with the Kelvin probe. A probable solution is presented, i.e. heating the ceramics so as to raise their electric conductivities high enough to root out the surface charges