Study On Resistance Switching In Metal Doped Strontium Titanate Single Crystal

With the rapid development of science and the changing of human needs,it is important to the development of information technology.In the near future,the traditional storage technology will be touched by the miniaturization of the continuous competition of small electronic devices.In the past few years,a lot of work has been done in order to obtain new materials and techniques to overcome this problem.Recently,the resistive random access memory has attracted significant attention because of its simple structure,fast switching,high scalability as the next generation non-volatile memory applications.Nonvolatile resistance switching memory is based on type electronic pulse induced resistance,by applying an electric field on the electrode to inspire the system resistance mutation,can be observed in the transition metal oxides,for example NiO,TiO₂,Nb₂O₅,SrTiO_x,PLCMO,PCMO and YBCO.Several models have been presented to describe the mechanism of induced electric impulse resistance effect,it can be divided into two main categories,capacity limit and the limit surface conduction mechanism.Capacity limits also includes a series of model transmission linear model,the effect of space charge limited current and frank.The surface conduction limiting mechanism also includes some models,such as ion electrochemical migration?e.g.oxygen vacancies?,carrier capture?electron and hole?,Mott transition is deposited on the carrier induced interface.Although a lot of effort was made to understand the type electronic pulse induced resistance effect,induced electronic pulse resistance effect of the physical origin has been extensive debate,the researchers found that the resistance switch phenomenon exists in the oxide materials,oxide electrically induced resistance changing memory has simple structure,low power consumption,high speed and reduces the size of excellent wipe advantages,the application prospect is very bright.In the development of it in the past for a long time,however,is still not to elucidate the mechanism of resistance change,even the same material of same structure device,the interpretation of the mechanism of resistance change is not unified,which leads to the development of such memory constrained,also hindered its practical application.As a result,reveal the true mechanism of the electrical resistance to change is a very important subject currently In many oxide materials,the SrTiO₃ materials with perovskite structure have obvious advantages:it is easy to realize the modulation of the components and the photoelectric properties by doping elements.In recent years,people found that the electrical resistance switching phenomenon in a variety of excellent elements doped SrTiO₃,perovskite structure of neodymium doped strontium titanate?NdSTO?and niobium doped strontium titanate?NSTO?crystal has stable chemical properties and structure.It is easy to analyze the mechanism of resistance change by establishing a simple and non-sandwich structure.By different doping concentration,can form a donor or acceptor level in the band gap,and some metal contact to form ohmic junction or Schottky junction,by electric pulse excitation to the resistive material under different resistance state.The doped NSTO and I-V resistance with different means of testing,effects of temperature and doping concentration on the resistance switching.Under the above background,this article has carried on the NdSrTiO₃ single crystal resistance switching phenomena and temperature resistance switching phenomena under study,some meaningful results are obtained,as follows:1.Pt/NdSTO/In were prepared by a resistive device,the device resistance some performance tests were carried out,such as the I-V cycle,multilevel storage and fatigue,maintain time effect on the device,the effect of light,temperature and so on.It is concluded that the cause of the change is the carrier trapping and escaping in the Schottky barrier.It is found that the system has stable performance.The Schottky barrier model was established,and its mechanism was explored.2.Design a temperature probe,which greatly facilitates the temperature test,provide help for our experiments.The detachable electrode device is independently arranged with the probe station test chamber connection,ensure probe station in test chamber to move freely in the sample when the sample size is too large or even for placement of a deviation,and through adjusting the probe position,the sample is in the center position of the test chamber,ensure the closed test chamber when the cover will not lead to the sample and probe the fault,to ensure the safety of the sample electrode.3.Study of the strontium titanate doped with different Nb concentrations in variable temperature environment resistance,presumably because of initial temperature affect the Schottky barrier height,cause the change of the low resistance.