Performance comparison of pentacene organic field-effect transistors with SiO2 modified with octyltrichlorosilane or octadecyltrichlorosilane

Performance of pentacene organic field-effect transistors (OFETs) is significantly improved by treatment of SiO2 with octyltrichlorosilane (OTS-8) compared to octadecyltrichlorosilane (OTS-18). The average hole mobility in these OFETs is increased from 0.4 to 0.8 cm2/Vs when treating the dielectric with OTS-8 versus OTS-18 treated devices. The atomic force microscope (AFM) images show that the OTS-8 treated surface produces much larger grains of pentacene (∼500 nm) compared to OTS-18 (∼100 nm). X-ray diffraction (XRD) results confirmed that the pentacene on OTS-8 is more crystalline compared to the pentacene on OTS-18, resulting in higher hole mobility.

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► Comparison of pentacene OFETs upon SiO2 modification with OTS-8 and OTS-18.
► Larger grains and higher degree of crystallinity observed with pentacene on OTS-8.
► Field-effect mobility improved from 0.4 cm2/Vs for OTS-18 to 0.8 cm2/Vs for OTS-8.
► Mobility increase due to larger grain sizes and higher crystallinity in pentacene.