| Summary: | 碩士 === 國立雲林科技大學 === 光學電子工程研究所 === 96 === In this research, We discussed that the use of CL-PVP as the gate insulators in flexible organic thin-film transistors. The different mixing concentration ratios of cross linking is 1:1、5:1、10:1、20:1 and the different baking temperature of cross linking is 150 ℃、160 ℃、170 ℃、180 ℃、190 ℃ and 200 ℃ in gate insulators of processing conditions. The electricity of the organic thin film transistor was affected by CL-PVP gate insulators under different annealing conditions.
The first experiment is the making of the organic thin-film capacitor. We fabricated the MIM capacitors with Al/CL-PVP/Al structure. First, the Al electrode was deposited on the plastic substrates. Second, We fabricated different concentration ratios of cross linking and the different baking temperature of cross linking in gate insulators. Finally, the Al electrode was patterned by the metal mask and was deposited on the insulator of CL-PVP. The results showed the largest capacitance per unit area was Ci（PVP:PMF = 20:1）=67.39 nF/cm2、Ci（temperature of cross linking = 200 ℃）=54.77 nF/cm2 respectively. The lower leakage current density are J（PVP:PMF = 10:1）= -2.44×10-7A/cm2、J（temperature of cross linking = 200 ℃）= -1.82×10-7 A/cm2 respectively.
The second experiment is to apply the results of the first experiment in the flexible OTFT devices. The devices have four major layers: gate electrode, organic gate insulator layer, organic active layer and source/drain electrode. We use thermal evaporator and different masks to grow the thin films except the organic gate insulator layer, which is fabricated by spin coating technique. The results showed the best mobility are μ（PVP:PMF = 10:1）or（temperature of cross linking = 180 ℃）= 0.074 cm2/Vs. The results showed the best on/off current ratio are Ion/off（PVP:PMF = 10:1）= 1.4×105、Ion/off（temperature of cross linking = 200 ℃）= 1.5×105. According to the results of pentacene and CL-PVP surface analyzed by AFM, the results showed that we can get larger Pentacene grains and lower leakage current on the lower roughness of CL-PVP gate insulators to increase the mobility and on/off current ratio of the devices.
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