The Study Of Improving The Effect Of OTFT Injection Based On The Control Of Electrode Interface

Organic thin film transistor（OTFT） has broad application prospects due to a wide range of materials, simple production process of and the advantages of flexible substrate. Among many factors that affect the performance of OTFT devices, the quality of metal semiconductor interface is a very important aspect. Actually, due to the mismatch of the electrode and the semiconductor energy level, most of the metal semiconductor contacts are Schottky contact. This paper based on the control electrode interface function to improve injection effect of thin film devices.Firstly, the metal semiconductor contact interface is formed by metal electrode material and copper phthalocyanine, and the energy level structure and the electric field are analyzed, and the influence of the metal work function on the contact resistance is also analyzed. The influence of different electrode materials on the contact resistance of OTFT was analyzed, and the influence of the metal work function on the performance of OTFT device was analyzed. The Mo O₃ modified metal electrode was used to improve the energy level of copper phthalocyanine HOMO and to reduce the contact barrier of metal semiconductor interface, so as to improve the carrier mobility of OTFT devices.Secondly, by optimizing the thickness of the modified layer of the Mo O₃ electrode, the optimal thickness of the device is obtained. The output characteristic curve of the three groups of different Mo O₃ modified layer thickness（0nm, 4nm, 8nm） was compared by many experiments. It shows that the performance of the 4nm insertion layer OTFT is more obvious than that of on the 8nm device. Through the analysis we can know that although Mo O₃ can reduce the Schottky barrier of the contact interface, the Mo O₃ is an insulator, which is equivalent to a series of resistors in series, which affects the transmission of the carrier.Finally, under laboratory conditions, the OTFT（Ni-Ag, Ag-Ni, Ni-Ni） with three different electrode structures were prepared by using copper phthalocyanine as a semiconductor material, and three different combinations of electrodes. And their contact resistance and the source drain current, output characteristic curve and the transfer characteristic curve of measurement and analysis, asymmetric electrode structure to improve car-rier mobility and switching ratio has obvious effect.