Abstract: The theory and experimental technique for the Isothermal Decay Current (IDC) method were discussed in this paper. The applications of the IDC method to α-CuPc, α-CuPc/PVK, Trans-PPA, DD-PPA thin films were described. The mean energy level E_m and distribution parameters _σ of Gaussian distributed traps fitted by multiple regression, the total occupied density of states N₀f₀ and the frequency factor v for the carrier detrapped were evaluated.

Key words: Isothermal Decay Current, Gaussian distributed traps, Trap level