Effect of Trap Property on Charge Transport Parameters of BaTiO3/polyimide Nanocomposites

Polymers and their nanocomposite films are quite attractive as dielectrics for energy-storage capacitors. To develop advanced polymer nanocomposites with high breakdown strength and large charge density, the breakdown mechanism must be further clarified. In this paper, the effect of trap property on the charge transport parameters of BaTiO3/polyimide nanocomposites (0 ~ 50 wt%) was studied. The carrier mobility and mean free path were extracted from the surface potential decay experimental results and the bipolar charge transport simulation results, which are respectively in the range of 6.2×10
^-15
~2.8×10
^-14
m
²
·V
^-1
·s
^-1
and 1.44 ~ 2.73 nm. The results show that, with the increment of average trap depth (0.44~0.85 eV), which is defined to describe trap property more clearly, the mean free path decreases linearly and the carrier mobility decreases exponentially. The effect mechanism of trap property on the mobility and free path was also discussed.