| Summary: | 碩士 === 國立成功大學 === 光電科學與工程研究所 === 96 === In this study, the structural and electrical transport properties of n-type copper hexadecafluorophthalocyanine (F16CuPc) thin-films as an active layer were investigated using organic thin films transistors (OTFTs). In part 1, we studied the influence of substrate temperature during thin-film growth of F16CuPc on the electrical characteristics and hysteresis effects in OTFTs using indium-tin-oxide (ITO) bottom contact and bottom gate device configuration. In part 2, we studied the effects of polymeric modification layers on the F16CuPc film growth and structural properties.
In part 1, we have fabricated OTFTs using the F16CuPc films which were thermally evaporated on different temperature SiO2 surfaces ranging from 30 to 180 ℃. The device characteristics were analyzed using the standard charge-sheet MOSFET model equation. These F16CuPc films were characterized by X-ray diffraction (XRD), absorption spectroscopy, and Raman spectroscopy. When the substrate temperature was set to 120 ℃, the corresponding F16CuPc-based OTFTs exhibit the highest field-effect mobility, the largest modulated on/off current ratio, the lowest subthreshold swing, and the smaller hysteresis loops. XRD and absorption spectra results could not give a reasonable explanation of the devices’ performance of F16CuPc-based OTFTs. In contrast, Raman analysis results indicated F16CuPc grown on 120 ℃ substrate has a more homogeneous molecular structure and microstructure associated with lower reorganization, thus device performance.
In part 2, the structural properties of F16CuPc films grown on various polymeric modification layers were investigated using contact angle meter, XRD, absorption spectroscopy, and Raman spectroscopy. Upon analyzing the surface free energy and interfacial adhesive force between F16CuPc and polymeric surfaces, we suggest that polymethylmethacrylate (PMMA) and polystyrene (PS) are the effective modification layers for the growth of F16CuPc film. The thin film structures of F16CuPc on polymeric modification layers, e.g. PMMA, PS, and poly(vinyl alcohol) are better than that on native SiO2 surfaces.
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