The effect of surface modification of dielectric layer on the morphology of deposited organic films and performance of field-effect transistors

• Main Authors: Zhi-wei Huang, 黃志瑋
• Other Authors: Yu-tai Tao
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/61874188504821960851

碩士 === 國立中央大學 === 化學研究所 === 96 === The thesis is divided into two parts. In the first part, several organic tri- -chlorosilane derivatives (4-alkyloxyphenyltrichlorosilane, n-alkyltrichlorosilane, phenyltrichlorosilane, heptadecafluoro-1,1,2,2,-tetrahyhrodecyltrichloro silane), were used to form single component or mixed self-assembled monolayers(SAM). Their structures were investigated by ATR-IR, elliposometry and contact angle measurement. The second part is about depositing pentacene thin on the above SAM-modified SiO2 dielectric surface. Effect of SAM modification on the structure and morphology of pentacene films were investigated by AFM and X-ray. Field effect transistors were also fabricated in order to correlate the field effect carrier mobility with the pentacene film structure/surface mofication. In the first part of the study, all single-component SAMs, except that for 4-alkyloxyphenyltrichlorosilane, are forming monolayers with nearly upright packing of the alkyl chains. The 4-alkyloxyphenyltrichlorosilane formed a monolayer with a larger tilt angle of the alkyl chains, presumably due to the packing of phenyl rings requires a larger spacing. Mixed SAMs gave higher surface energy than the single component SAMs, as judged from the contact angle. In the second part of study, it was shown that pentacene film deposited on a SAM that was rubbed first gave larger grains of better crystallinity compare to that deposited on SAM without rubbing treatment. Field effect carrier mobilities also increased with rubbing treatment along the rubbing direction. Pentacene film deposited on mixed SAMs prepared from 4-alkyloxyphenyltrichlorosilane and phenyltrichlorosilane gave smaller grains and poorer mobility, presumably due to the rougher surfaces provided by the mixed monolayer. For pentacene film deposited on silicon oxide surface modified by hepta- -decafluoro-1,1,2,2,-tetrahyhrodecyltrichlorosilane, a substantial current (6*10-4A) was observed at zero gate voltage. The strong negative dipole of CF3 group is suggested to induce hole carriers at the SAM/pentacene interface.