La-1.3Sr-1.7Mn2O7/SrTiO3-Nb异质结的整流和光伏特性  

Rectifying behavior and photovoltage effect in La_(1.3)Sr_(1.7)Mn_2O_7/SrTiO_3-Nb heterostructure

作　　者：张强[1] 王建元[1] 罗炳成[1] 邢辉[1] 金克新[1] 陈长乐[1] 

机构地区：[1]西北工业大学理学院,陕西省凝聚态结构与性质重点实验室,西安710072

出　　处：《物理学报》2016年第10期288-293,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51402240,51471134,51202195,51172183,61471301,51572222);陕西省自然基金(批准号:2014JQ6218);中央高校基本科研业务费(批准号:3102014KYJD026);西北工业大学翱翔新星人才计划资助的课题~~

摘　　要：采用脉冲激光沉积法在SrTiO_3:0.7%Nb(100)单晶衬底上生长了La_(1.3)Sr_(1.7)Mn_2O_7薄膜,并研究了LSMO/SrTiO_3-Nb异质结的输运性质和光伏效应.研究发现,异质结具有良好的整流特征和明显的光生伏特效应.在532 nm激光辐照下,光生电压随温度升高先增大后减小,并且在150 K达到最大值400 mV,此温度点与LSMO薄膜发生金属-绝缘体转变的温度一致,这表明异质结的光生伏特效应受LSMO薄膜内部的输运特征调控.进一步,从光生电压随时间的变化曲线中分析发现,上升沿符合一阶指数函数,这与载流子的迁移过程相关;而下降沿符合二阶指数函数,这与结两侧载流子的外部回路中和以及材料内部的电子-空穴湮灭有关.值得注意的是,上升沿和下降沿的时间常数均随着温度先增大后减小,且最大值均出现在LSMO薄膜的金属-绝缘转变温度.Perovskite oxide heterostructure possesses attractive magnetic,optical and electric properties,such as superconducting interface between two insulators,two-dimensional electron gas,positive giant magnetoresistance,photoelectric response characteristic,magnetocaloric effect,and coexistent different magnetic structures.Especially for the photoelectric response behaviors of A1-xA′xMnO3（A = La,Pr etc.;A′= Sr,Ca etc.）perovskite manganese oxide heterostructure,one has made a systematic study on the photoelectric conversion efficiency,the photovoltaic response speed,and the in-plane lateral photovoltage.Besides A1-xA′xMnO3 structure,manganese oxides can also exhibit the double layered perovskite structure A2-2xA′1＋2xMn2O7.Double layered perovskite structure can be regarded as the layers of perovskite and rock salt which are alternately stacked.This double layered perovskite manganese oxide（such as La2-2xSr-1＋2xMn2O7）is a natural structure of the tunnel structure：ferromagnetic metal layer-insulating layer-ferromagnetic metal layer.Double layered perovskite manganese oxide has not only the characteristics of giant magnetoresistance,but also the novel physical properties,such as persistent photoconductivity,etc.However,there are few reports on the physical properties of the double layered perovskite manganite oxides,heterostructures,especially the photovoltaic properties.In this work,the La-1.3Sr-1.7Mn2O7（LSMO）film is deposited on an n-type SrTiO3-Nb（NSTO）single crystal substrate by a pulsed laser deposition method.Additionally,we study the transporting properties of LSMO/NSTO heterostructure and its photovoltaic effect.The heterostructure exhibits benign rectifying and palpable photovoltaic effect.Under the 532 nm laser irradiation,the photovoltage first increases and then decreases with temperature rising.The maximal photovoltage reaches 400 m V at 150 K which is consistent with the metal-insulator transition temperature of LSMO film.It is indicated that the photovoltaic effect of the hetero

关 键 词：光生伏特效应 双层钙钛矿 异质结 载流子寿命 

分 类 号：TB383.2[一般工业技术—材料科学与工程]