Investigation Of The Effect Of Plasma Treatment On The Properties Of Schottky Contact And Thin Film Transistors Made From ZnO-based Thin Film And Nanostructure

As an important oxide semiconductor material, ZnO has been widely used in several kinds of devices due to its excellent optical and electrical properties. Among all these devices, ZnO-based thin film transistor has become one of the most promising devices in flat panel display because of its high carrier mobility, high optical transmittance and high reliability. In this work, we focus on three kinds of ZnO based material:ZnO films, ZnO nanorods, and MgInZnO (MIZO) films, and then investigate the effects of O2and Ar plasma treatment on properties of ZnO based material and devices.First of all, we fabricate ZnO films using sol-gel method and study the effect of O2and Ar plasma treatment on material properties of ZnO films. The result shows that Ar treatment can improve the PL properties of ZnO greatly. The ratio of UV peak intensity to visible light peak increases nearly100times. XPS result shows that plasma treatment can decrease intrinsic defects like oxygen vacancy as well as impurities absorbed at the surface of ZnO films and then improve the PL properties.In the second part, we prepare the ZnO nanorods and study the effect of O2and Ar plasma treatment on PL optical properties of ZnO nanorods. The ratio of UV peak to visible light peak reaches to2566:1after Ar plasma treatment. Then we fabricate ZnO nanorods/Pt Schottky contact and study the effect of Ar treatment on its electrical properties. The Schottky exhibits obvious rectified characteristics.We prepare MIZO films by sol-gel method, and investigate the effect of oxygen treatment on MIZO material feature. The XPS result shows oxygen treatment can effectively lower the content of defects in MIZO films. We also fabricate MIZO/Pt Schottky contact and find that MIZO films annealing at400℃for30min have the best Schottky properties with SBH of0.65eV and ideal factor of1.71. We further investigate the effect of oxygen treatment on properties of Schottky contact.At last, bottom-gate structured MIZO thin film transistors are prepared and we systematically study the influence of O2and Ar plasma treatment on TFT properties. We find out that both kinds of plasma treatment can increase the field effect mobility and on/off ratio is improved by almost two orders of magnitude. The electrical properties of MIZO-TFT are greatly improved with field effect mobility of1.43cm2/V·s and on/off ratio of106.