Study On Thiophene Nanofibers-based Transistors

In recent years, the distance between the source and the drain of the transistor which uses one-dimensional materials as the active layer is mostly 5-20μm as reported. The source and drain electrodes are made through photolithography. As a result, the photolithography process may affect the properties of the active layer. If the material of active layer is post-production, the material, the source and the drain electrodes achieve ohmic contact by electrostatic attraction. Thus the electrodes are not strong enough which can fall off sometimes. Therefore, the device structure commonly used is gate electrode / insulator / source drain / nano-organic materials / Pt electrode and the device is packaged afterwards. Device using the previous structure is very solid and the performance of it is good because of the good contaction between nano-materials and the electrode. However, the process of the device structure is complex and the cost is high.We designed a new transistor structure with relatively simple process.By means of gas-phase polymerization between electrostatic spinning and organic materials, we produced the ordered arrangement of the polythiophene nano-fiber array. We further produced the transistors based on the polythiophene nano-fibers arrays. The device shows P-type characteristics with great on-off current ratio which is up to 4×105 when Vds is 2V.Besides,the device has a low threshold voltage which is about 1 V and the carrier mobilityμis 14.9 cm~2/Vs when Vds is 2V.In the end, we made a device structure with simple process and low cost. We used the low cost general thiophene as raw materials and produced nano-fiber thin film field-effect transistor whose mobility reached 14.9 cm2/Vs by the means of gold-doped. This data even exceeded that of P3HT (a thiophene derivative) transistors which is widely used currently and is more expensive. It can be said that the one-dimensional gold-doped polythiophene nanofibers and its device structure have some application potential in the field of OTFT.