Engineering gate dielectric surface properties for enhanced polymer field-effect transistor performance

摘要

The modification of silicon dioxide (SiO2) gate dielectrics with silane self-assembled monolayers (SAMs) via silylation was conducted to study their impacts on polymer field-effect transistor (FET) performance. SAMs formed from silylating agents with long alkyl chains such as octadecyl gave high field-effect mobility but a lower on/off ratio because of lower SAM coverage of the gate dielectric surface. In contrast, SAMs from silylating agents with phenyl or medium alkyl chains (octyl) provided a high on/off ratio from high SAM surface coverage but lower mobility due to their inefficiency in promoting molecular ordering of the channel semiconductor. By treating the SiO2 dielectric surface with two silylating agents, one with an octadecyl chain and one with an octyl or phenyl chain, in a proper sequence, a high-performance "hybrid'' dual-silane SAM could be created, enabling attainment of both a high mobility and on/off ratio, together with other desirable FET properties.