Space charge behavior and luminescence phenomenon in polymers at 77K

The electroluminescence phenomenon was observed at a needle tip of polymer samples with a point-plane electrode system under an ac voltage application in liquid nitrogen temperature region. The injected space charges were found to be responsible for this luminescence and thier roles of deforming the needle tip field were discussed. Also the effect of an ac voltage application for a long period on the tree initiation of polymer materials was studied.