薄膜厚度对La_(0.8)Sr_(0.2)MnO_3/TiO_2PN结整流特性的影响

Influence of thickness on rectifying properties of La_(0.8)Sr_(0.2)MnO_3/TiO_2PN junctions

采用磁控溅射法制备了La0.8Sr0.2MnO3(100nm;50nm;17nm)/TiO2(70nm)异质PN结,并对其进行电学性能研究。结果显示样品均表现出很好的整流特性。并且在La0.8Sr0.2MnO3/TiO2异质PN结中,当LSMO膜厚较薄时,由于LSMO薄膜与衬底之间的较高的应力局限了载流子浓度,导致扩散电压减小。变温电流电压特性曲线显示随着测量温度的降低,扩散电压增大,这可能由于随着测量温度的变化导致界面电子结构的变化。值得提出的,异质PN结结电阻随温度变化曲线表现出单层LSMO具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,这可能是由于宽带隙的TiO2的引入造成的。

The La0.8Sr0.2MnO3 （100 nm; 50 nm; 17 nm）/TiO2（70 nm） PN hetero junctions are synthesized by RF magnetron sputtering and the electrical properties of these samples are studied. The result shows that these samples have good rectifying properties. Besidesd, La0.8Sr0.2MnO3 （LSMO）/TiO2 with thin LSMO film has small diffusion potential, which results in the decrease carrier concentration because of the larger strain between film and substrates. It is noted that the heterogeneous PN knot forms electric resistance with the temperature change curve to show the metal insulation transition characteristic possessed by single layer LSMO, and at low temperature the knot electric resistance becomes stronger with the decreasing of temperature, which may be due to the introduction of TiO2 for broadband.