In this study, vacuum-evaporated thin films of several naphthalene tetracarboxylic acid diimide derivatives substituted at the N and N′ positions with long normal alkyl chains of varying lengths (NTCDI-Cn) were evaluated as active materials for n-type organic thin-film transistors (TFTs). The electron mobility (μe) of the TFTs increased with increasing chain length from octyl (NTCDI-C8) to pentadecyl (NTCDI-C15); those of NTCDI-C15 and C18 TFTs were of 0.262 ± 0.016 and 0.222 ± 0.016 cm2 V−1 s−1, respectively. However, the threshold voltage of the TFTs increased with increasing chain length.
We compare the fundamental electric properties of Cu-poor and Cu-rich Cu(In,Ga)S 2 films before and after annealing, respectively. It has been found that the hole density of Cu-poor films increases after annealing in a O 2 +S combined atmosphere, whereas annealing in S only does not produce a significant effect. We conclude that the oxygen is effective for the passivation of donor-type defects in the Cu-poor Cu(In,Ga)S 2 films. In the case of Cu-rich films, the hole density also increases with O 2 +S-annealing. However, annealing in sulphur atmosphere (no oxygen gas) in this case has comparable consequences. These observations suggest fundamental differences in the incorporation mechanisms of oxygen and sulphur in both types of the film. A tentative model is presented, taking into account results from microstructural characterization of the films.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.