衬底温度对La0.8Sr0.2MnO3/TiO2异质P-N结整流特性的影响  

EFFECT OF SUBSTRATE TEMPERATURE ON RECTIFYING PROPERTIES OF La_(0.8)Sr_(0.2)MnO_3/TiO_2 P-N HETEROJUNCTIONS

作　　者：李彤[1,2] 刘盾[1] 裴志军[1] 王雅欣[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,北京100022

出　　处：《低温物理学报》2008年第4期330-335,共6页Low Temperature Physical Letters

摘　　要：本文利用磁控溅射法通过改变衬底温度成功制备出La_(0.8)Sr_(0.2)MnO_3(LSMO)/TiO_2异质P-N结.当衬底温度升高时,LSMO/TiO2异质PN结表现出相对较好的整流特性.这可能是由于衬底温度的升高导致氧气吸收的增加,进而导致载流子浓度增大,串联电阻降低.电流电压的变温特性曲线显示随着测量温度的降低,扩散电压增大,这可能由于能带结构模型与热激活模型共同决定.值得提出的,异质P-N结结电阻随温度变化曲线呈现出单层LSMO表现的金属绝缘相变特性,并且在低测量温度时表现出随着测量温度的降低结电阻增大,这可能是由于宽带隙的TiO2的引入导致.The La0.8 Sr0.2 MnO3 （ LSMO）/TiO2 heterojunctions were synthesized by RF magnetron sputtering technique at the different substrate temperatures. Relatively good rectifying property is shown in the hetero- junction when the substrate temperature is increased. This behavior can be attributed to the increased carrier concentration and the decreased serial resistance due to absorption of oxygen with substrate temperature. From I-V curves with measurement temperature, the diffusion potential decreases with increasing measurement temperature, which is ascribed to the modulation of interface electronic structure of LSMO/ TiO2 heterojunction and thermal acitivation. It is worth noting that LSMO/TiO2 heterojunctions show the Metal-Insulator （M-l） transition of LSMO single films. Furthermore, the increased junction resistances of heterostruetures at low temperature may be related to the introduction of TiO2.

关 键 词：异质结 整流特性 庞磁阻 

分 类 号：O475[理学—半导体物理]