PMMA栅绝缘层表面形貌对并五苯OTFT性能的影响

Effect of the Surface Morphology of the PMMA Gate Insulating Layer on the Performance of the Pentacene-Based OTFT

影响有机薄膜晶体管(organic thin-film transistor,OTFT)器件性能的主要因素中,栅绝缘层表面形貌特性和薄膜厚度等有着非常关键的作用,会直接影响有源层材料的分子排列方式和整个器件的性能。以氧化铟锡(ITO)导电薄膜玻璃为衬底材料,采用溶液旋涂的工艺制备聚合物聚甲基丙烯酸甲酯(PMMA)有机绝缘层,采用真空蒸镀的方法制备并五苯有源层及源-漏银电极。通过对比不同退火条件下PMMA绝缘栅层表面形貌及粗糙度,制备适合有源层生长的绝缘层表面,得到较好的PMMA栅绝缘层/并五苯有源层界面接触。实验表明,PMMA栅绝缘层经退火后所制备的器件场效应迁移率提高到2.52×10-3 cm2/(V·s),阈值电压降低到-11.5 V,获得了性能较好的OTFT。

The main influence factors of the organic thin-film transistor（OTFT）performances including the surface morphology characteristics of the gate insulating layer and thin-film thickness,etc.directly affect the molecular arrangement of the active layer materials and the performances of the device.With the indium tin oxide（ITO）conductive film glass as the substrate material,the polymethyl methacrylate（PMMA）as an organic insulating layer was prepared by solution spin-coating method,and the pentacene active layer and source-drain silver electrodes were prepared by the vacuum evaporation method.By comparing the surface morphologies and roughnesses of the PMMA insulating layer at different annealing conditions,the surface of the insulating layer suitable for the growth of the active layer was prepared to obtain a better interface contact between the PMMA gate insulating layer and pentacene active layer.The experiment shows that the field effect mobility of the device with the annealed PMMA gate insulating layer increases to2.52×10-3 cm2/（V·s）and the threshold voltage reduces to-11.5 V,obtaining the OTFT with better performances.