Trap-controlled hopping in HDPE

Based on measurements of the isothermal surface potential kinetics the charge carrier transport in HDPE is investigated. A simple mathematical model for discribing the surface potential kinetics is presented involving hopping transport of injected charge carriers being modulated by shallow and deep traps at the surface and in the bulk. The model parameters, as charge carrier mobility, hopping distance, trap concentration, trap depth and attempt-to-escape frequency were determined by curve fitting. The resulting dependence of mobility and lifetime on the field strength is discussed.