Preparation Of Rare Earth Elements Doped CCTO Thin Films And Study On Their Nonlinear ?-? Characteristics

Copper calcium titanate CaCu₃Ti₄O₁₂?CCTO?is an excellent dielectric material,which has a considerable dielectric constant.At the same time,it can maintain a good stability in the temperature range of 100K to 400K.Significant current-voltage??-??characteristics also indicate that CCTO has broad potential in applications such as capacitance and voltage-sensitive resistance.At the same time,compared with CCTO ceramics,the thin film materials prepared by CCTO have the problems of nonlinear coefficient,and the related properties are still controversial.Therefore,the research on CCTO film has not only theoretical significance,but also practical application value.In this paper,CCTO thin films were fabricated on the Pt/Ti/SiO₂/Si substrate and a series of rare earth elements?La Pr Sm?were used to modify the CCTO on the improved sol-gel method.The prepared films were characterized by XRD and SEM.The influence of the doping content on the properties of CCTO thin films were studied by using the doping increment method for different rare earth elements.The results showed that the CCTO films with good morphology and good grain shape were obtained in this study.CCTO thin films have obvious nonlinear ?-? characteristics,and proper rare earth doping can improve the nonlinear properties of CCTO thin films.In addition,the crystal structure and grain size of CCTO also change regularly with the doping amount of rare earth elements,while the three kinds of rare earth elements also show different effects on the properties of CCTO films.In this paper,the double Schottky barrier?DSB?model is used to explain the nonlinear properties of CCTO films.The reason for nonlinearity is the semiconducting grains and low resistance of the grain boundary after sintering process.According to this model,the doping modification results of rare earth elements were explained.