Electrical Properties of Copper Phthalocyanine Thin Films as Influenced by the Ambient

Abstract

Measurements of currents in evaporated thin films of copper phthalocyanine as a function of temperature and ambient have yielded information about the effects of nitrogen, hydrogen, and oxygen ambients on the conductivity, trap density, and mobility. Above a transition voltage the currents are space‐charge‐limited and can be correlated with a trap distribution that decreases exponentially with energy as the distance from the valence band edge increases. The parameters that govern the distribution as well as the position of the Fermi level depend on sample preparation, and some systematic correlation exists between annealing and the subsequent values of these parameters, based on consideration of the crystal changes that occurs on heating. The value of the intrinsic conductivity σ₀=3(Ω cm)⁻¹ and mobility μ=0.013±0.007 cm²/Vsec have been determined and are found to be relatively independent of preparation and subsequent treatment.