THz Detecive OFET Fabrication And Performance Study

Terahertz waves have the advantage of low photon energy and non-ionization characteristics compared to X-rays,and the destruction of the organism or material is very small,which can penetrate some specific material.Terahertz wave imaging technology will have important applications in the medical diagnosis,safety detection and communication,and other fields in the future.The organic field effect transistor(OFET)has the advantages of light weight,low cost,large area and suitable for mass production,and the maximum fluctuation of the pentacene HOMO band is 30meV,which is close to the THz wave of the photon energy(0.41-41 meV).Therefore,this paper presents that pentacene OFET can be used for the detection of THz wave.In this paper,the structure of the cross in-line was used as the structure of source and drain electrodes,low-doped n-type silicon with high resistivity(1-5?·cm) was used as substrate and bottom-gate,pentacene was used active layer material,and the THz detection OFET device was prepared.Firstly,the effect of substrate temperature on the performance of the device was discussed.We deposited pentacene at different substrate temperatures to prepare the OFET device,analyzed and compared the performance of the device,and obtained the optimum substrate temperature.Secondly,the optimum temperature of the substrate was maintained,and the effect of surface treatment on the performance of the device was discussed.The reason why surface treatment can change the performance of the device was analyzed.Then,the effect of electrode material on the performance of the device was discussed.We fabricated OFET device with metal Cu and Au as S/D electrode under the same process conditions.The performance of the device was compared and the reason why electrode material can change the performance of the device was analyzed.Finally,the influence of the cross-row electrode structure on the electric field of the THz wave was simulated by FDTD.The THz-TDS was used to measure the absorption spectrum of the THz wave.The simulation results were compared with the results of the test,providing theoretical support for optimizing S/D electrode structure.The results showed that the OFET device has the best performance and the maximum mobility of the linear region when Au was used as the S/D electrode under the condition of optimal substrate temperature of 90? and HMDS surface treatment,the average mobility of the linear region carriers was 0.97cm²V^-1s^-1,and the threshold voltage was near -0.1 V.In addition,we found that FDTD simulation was a very effective method to optimize the S/D electrode structure.