Ta2O5-PMMA复合栅绝缘层对OFETs性能的影响

选用五氧化二钽（Ta₂O₅）-聚甲基丙烯酸甲酯（PMMA）复合材料作为栅绝缘层制备了并五苯有机场效应晶体管（OFETs）。通过在Ta₂O₅表面旋涂一层PMMA可以降低栅绝缘层的表面粗糙度，增大其场效应晶体管的迁移率。研究了厚度在20~60 nm范围内的PMMA对复合绝缘层表面形貌、粗糙度以及器件电学性能的影响。结果表明，当PMMA厚度为40 nm时，器件的电学性能最佳。与单一的Ta₂O₅栅绝缘层器件相比，其场效迁移率由4.2×10^-2 cm²/（V·s）提高到0.31 cm²/（V·s）；栅电压增加到-20 V时，开关电流比由2.9×10²增大到2.9×10⁵。

Effect of Ta2 O5 -PMMA Compound Gate Insulator on The Performance of Organic Field Effect Transistors

This paper reports pentacene field effect transistors (OFETs) with a gate insulator made of compound Ta2 O5-PMMA where PMMA (poly (methyl methacrylate)) is spin-coated onto the top of evaporated layer of Ta2 O5 . A comparison with devices with only Ta2 O5 is presented. The latter not only shows a high surface roughness but also exhibits very low field-effect mobility. These drawbacks can be overcome by depositing a PMMA layer on Ta2 O5 . The influence of PMMA thickness in the range 20 - 60 nm is presented. The results show that when the thickness of PM-MA is approximately 40 nm, the electrical performance of OFETs is optimal. Compared with conventional OFETs, the field-effect mobility increases from 4. 2 × 10 - 2 to 0. 31 cm2 / (V·s), and the on/ off current ratio increases from 2. 9 × 102 to 2. 9 × 105 when the gate voltage increases to - 20 V.