Space-charge-limited current theory for molecular crystals with gaussian distribution of local trapping states

Abstract

A phenomenological space-charge-limited current (SCLC) theory for molecular crystals with local charge carrier trapping states of Gaussian distribution is presented. Two distinct types: conductivity level edge Ge(E) and forbidden energy gap Gg(E) Gaussian trap distributions are discussed. The validity range for various analytical approximations of the currentvoltage (I-U) characteristics for Gaussian trap distribution is analysed and the validity criteria for Ge(E), Gg(E), and the exponential trap distributions are presented. Other important SCLC theory relationships, such as the dependence of the I-U characteristic on the Gaussian distribution parameters σ and Et, temperature, and sample thickness are also discussed in some detail. Several calculated I-U characteristics for crystals with a set of double Gaussian distributions are presented. Calculated SCLC theory dependences and main validity criteria are illustrated by experimental data. [Russian Text Ignored.]