Effect of Nano-SiO₂ films on electron radiation induced conductivity of polyimide

The radiation induced conductivity (RIC) behaviors in nano-SiO₂ deposited polyimide (PI) were investigated using in situ measurement technique. The results indicate that, by comparison with the case of virgin polyimide, the RIC in nano-SiO₂/polyimide shows low steady state values. Moreover, the steady state RIC is a power function of the dose rate with a power index of 0.659, lower than that of 0.76 in the virgin polyimide. The interfacial barrier and trapping effects are the main reasons for the change. Meanwhile, both of the interfacial effects also result in a unipolar carrier transportation mechanism in nano-SiO₂ deposited PI from the dipolar one in the virgin PI. The mechanisms of the RIC behaviors are discussed in the paper.