Study on the distribution of trap levels in PI by OPO laser

In this paper, the photo-stimulated discharge (PSD) current spectra of polyimide (PI) are obtained by the optical parametric oscillator (OPO) laser to characterize the deep space charge traps in the dielectric materials. The result shows that the energy level of charge traps in the PI film is distributed in 3.10~4.10eV, and the main part concentrates in 3.35~3.85eV. These data can provide experimental basis for the further research and improvement on electrical properties of materials.