薄膜厚度对La_(0.85)Sr_(0.15)MnO_3/TiO_2异质pn结的整流特性的影响  

Effect of Thickness on the Rectifying Properties of La_(0.85)Sr_(0.15)MnO_3/TiO_2 Heterostructures

作　　者：李彤[1] 裴志军[1] 孙守梅[1] 马兴兵[1] 冯立营[1] 张铭[2] 严辉[2] 

机构地区：[1]天津工程师范学院电子工程系,天津300222 [2]北京工业大学材料科学与工程学院薄膜实验室,北京100022

出　　处：《Journal of Semiconductors》2008年第9期1794-1798,共5页半导体学报（英文版）

基　　金：天津工程师范学院科研启动基金资助项目(批准号:KYQD07002)~~

摘　　要：采用磁控溅射法制备的La0.85Sr0.15MnO3（100nm;5.0nm;17nm）/TiO2（70nm）异质pn结表现出明显的整流特性,其中La0.85Sr0.15MnO3（100nm）/TiO2异质pn结所呈现的整流特性相对较好,同时发现该整流特性在很宽的测量温度范围（80~320K）内存在.通过拟合发现,所有样品都呈现很大的串联电阻,并且串联电阻对整流特性有很大的影响.变温电流电压特性曲线显示随着测量温度的降低,结电压增大,这可能是由于随着测量温度的变化导致界面电子结构的变化.应该指出的是,La0.85Sr0.15MnO3/TiO2异质pn结结电阻随温度变化曲线显示出单层LSMO所特有的金属绝缘相变特性,并且在低温测量时,结电阻随着测量温度的降低而增大,这个变化趋势也同拟合后的串联电阻变化趋势相似.La0.85Sr0.15MnO3/TiO2 heterostructures are synthesized by RF magnetron sputtering with different LSMO thicknesses. The rectifying properties of the junctions are related to the LSMO thickness and good rectifying properties appear in the LSMO（100nm）/TiO2 junction. Furthermore, an excellent rectifying characteristic is presented over a relatively wide temperature range for LSMO（100nm）/TiO2 heterostructures. All samples exhibit a huge effective resistance,which plays an important role in the 1- V curves as well as the rectifying properties. The diffusion potential of the heterostructures decreases as the measurement temperature increases,which is attributed to the modulation of the interface electronic structure of LSMO/TiO2 heterostructures. The metalinsulator （M-I） transition of LSMO also appears in the heterostructures and the increased sheet-resistance of heterostructures at low temperature is related to the introduction of effective resistance.

关 键 词：异质结 整流 庞磁电阻 

分 类 号：TN301.1[电子电信—物理电子学]