The Research On The Charge Transport Of Graphene Oxide And Typical Organic Polymer In Diode Storage Devices

Organic polymer materials can not only realize the function of the inorganic semiconductor materials in the field of such as information display and storage, but also have the characteristics of high mechanical strength, diverse, designable, flexible, ultrathin, suitable for printing large area and low cost of preparation. Due to the simple device structure and fabrication technology, large on/off current ratio and stackable features, organic diode memory devices is widely concerned by people. However, organic diode memory still exist many problems, such as poor repeatability, unstable performance, confusing storage mechanism. Therefore, to study the electrical transport process of the typical organic polymer materials in the diode device and observe the Current- Voltage curve of the device is an important way to understand the mechanism of the diode memory. The work of this thesis focuses on the dielectric properties and semiconducting properties of typical organic materials to the performance of the device.1、For the typical dielectric material, graphene oxide, we found that when the GO film thickness is greater than 300 nm, the ITO/GO/Al diode device has the characteristics of dynamic random access memory, excellent reading, writing and erasing performance under the action of voltage pulse cycle, large on/off current ratio, good stability and high repeatability. By analyzing the I-V characteristic curve of the device, it is inferred that the current hysteresis phenomenon is caused by the dielectric property of GO, and we used the piezoelectric atomic force microscopy(PFM) confirm that GO with ferroelectric properties. At the same time, we found that the diode device based on GO with the thickness and electrode dependence effect, we speculated that the device is affected by the migration of oxygen in the GO film.2、Based on the finding in the GO diode device, and the organic conjugated polymer material has the semiconducting properties, we studied the electrical transport process of the conjugated polymer PFO in the ITO/PFO/Al diode device. By controlling the scope of the test voltage, film thickness, we tested the I-V characteristics of the device. The device appeared approximate symmetrical current hysteresis curve in the low voltage region showing the dielectric properties; and appeared forward rectification and associated with the current hysteresis phenomenon in the high voltage region showing the semiconducting properties. The thickness effect of the device was also studied. Under the same conditions, the thinner film devices were more prone to the phenomenon of rectification. The dielectric properties and semiconducting properties of typical π-conjugated polymer to the device performance helps people to better understand its prospect in organic diode memory.3、As a contrast test, we continue to study the electrical transport process of diode devices of a typical stacking polymer PVK and a typical dielectric material PMMA. Similarly, the PVK-based diode device showed the dielectric properties in the low voltage region, and showed the semiconductor properties in the high voltage region. At the same time, under the same conditions, the thinner film devices were more likely to show semiconducting properties. We fabricated the PVK-based diode memristor ITO/PEDOT:PSS/PVK/Al. In the typical dielectric material PMMA diode device, the device appeared symmetrical current hysteresis curve in low voltage region, showing the dielectric properties, and in the high voltage region, the device did not appear smooth current curve, the current curve was interrupted, without showing the semiconducting properties.