The effects of electron (e)-beam irradiation on the luminescent and the materials properties of CaS: Pb films were investigated using structural and compositional analysis techniques. Continuous e-beam irradiation on CaS: Pb thin film for 180 min resulted in an approximately 60% decrease of cathodoluminescence (CL) intensity. Transmission electron microscopic analysis indicated that e-beam irradiation induced the precipitation of Pb. The decrease of CL intensity by e-beam irradiation was mostly caused by the decrease of Pb2+ luminescent center ion concentration due to the precipitation of Pb. E-beam irradiation also resulted in heavy carbonaceous contamination on the surface. The thickness of the carbonaceous layer was approximately 10 nm. (C) 2002 The Electrochemical Society.