Resistive Switching Memory And Synaptic Emulation Of Triphenylamine-based Polymer

In 1971, Leon O. Chua predicted the existence of memristor. In 2008, HP verifies its existence in experiment for the first time. In recent year, because of the special electrical property, memristor have been extensively researched for the application of resistive random access memory(RRAM) and synaptic emulation. Memristor is considered as one of the most powerful candidate of the next generation memory due to its good scalability, high operation speed and high density. In the meantime, the non-linear transmission and conduction controlled by applied voltage make memristor resemble the synapse. In this paper, we prepared various memristors based on triphenylamine and research their memory application and synaptic emulation.In chapter 1, we summarized the history and research state of memristor, RRAM and synaptic emulation. Focusing on some key problems in each field, we present the possible solutions. In the end, we explore the content and significance of this thesis.In chapter 2, in order to avoid the formation of aggregation of linear polymer, we design and synthesize two kinds of poly(azomethine)s(PAMs) with linear and hyperbranched structure. Compared to linear PAM, the hyperbranched PAM exhibit stable high resistance state, low resistance state, good cycle performance and good antifatigue properties.In chapter 3, to improve the ON/OFF ratio and thermal stability of RRAM, we prepared poly(triphenylamine)(PTPA). Pt/PTPA/Ta devices exhibit bipolar resistive switching. The set voltages increase linearly with the thickness of functional layer and reset voltages remain unchanged. The ON/OFF ratio of Pt/PTPA 90nm/Ta is 108 and the memory device could work at the temperature from 30 K to 390 K. The resistive switching mechanism of PTPA film is the formation and rupture of conductive filament observed by conductive- atomic force microscope(C-AFM).In chapter 4, in order to expand the material field and take advantage of the polymer material, we synthesized BTPA-F. The Pt/BTPA-F/EV(ClO4)2/Ta memristor was utilized to emulate some functions of synapse, such as potentiation, depression, learning, forgetting, spike rate dependent plasticity(SRDP) and spike timing dependent plasticity(STDP).In chapter 5, we summarize the research results of this paper and anticipate the future research direction.