TSC transport peak in phenothiazine-doped anthracene crystals

Thermally stimulated current (TSC) spectra have been measured in crystals of the organic photoconductor anthracene containing various amounts of phenothiazine, a dopant which forms relatively deep hole traps. In order to confirm theoretical predictions of recently proposed TSC 'transport peak' model, the electric field and thickness dependences of the TSC have been studied. It is found that the position of the TSC peak which is due to the phenothiazine trap varies in a systematic way with the applied electric field, allowing calculation of the trap parameters and determination of the temperature dependence of the effective trap-controlled mobility of holes. The traps formed by phenothiazine display a relatively narrow energy distribution and the charge carrier transport in the doped crystals bears a dispersive character.