Dependence of the electrical characteristics of organic-on-inorganic semiconductor contact barrier diodes on organic thin-film composition

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Abstract
Several aromatic compounds (such as 3,4,9,10 perylenetetracarboxylic dianhydride) have previously been reported to form rectifying heterojunction energy barriers when vacuum deposited onto inorganic semiconductor substrates such as Si, GaAs, and InP. In this paper we report the formation of rectifying heterojunction barriers using phthalocyanine‐based compounds layered onto p‐Si substrates. In many respects, the characteristics of phthalocyanine/Si heterojunctions are similar to those formed using the aromatic anhydrides insofar as the electrical properties can be explained using the thermionic emission space‐charge‐limited transport model introduced in previous work. However, in contrast to the earlier results, we find that a high density of surface states exist at the phthalocyanine/Si interface. Quantitative study of the interface state density provides insight into the mechanisms of formation of the organic‐on‐inorganic energy barrier.