LCMO,LSMO单、双层薄膜的制备和电学性质

Preparation and electric properties of single and double thin film of LCMO and LSMO

采用脉冲激光沉积法在Si衬底上沉积La1-xCaxMnO3,La1-xSrxMnO3(x=0.2,0.5,0.8)单钙钛矿锰氧化物单层膜和双层膜.采用LCR仪等分析测试手段研究了薄膜异质结的电流-电压特性.I-V特性曲线表明:单钙钛矿La1-xCaxMnO3/Si和La1-xSrxMnO3/Si均表现出了与传统p-n结相似的整流特性,但是La1-xCaxMnO3/Si的整流特性要明显优于La1-xSrxMnO3/Si,这可能是因为La1-xCaxMnO3同衬底晶格常数更为匹配且Sr掺杂引起的晶格畸变场势阱更深的缘故.在双层膜结构中可能是由于能带结构的原因,按La1-xSrxMnO3/La1-xCaxMnO3/Si顺序排列的异质结相当于p+-p-n结构,I-V特性明显类似传统的整流特性,而La1-xCaxMnO3/La1-xSrxMnO3/Si顺序的异质结相当于n-p-n型,整流特性不明显.

La1-xCaxMnO3,La1-xSrxMnO3 single and double thin films are prepared by pulsed laser deposition （PLD） on the Si（100） substrate. The transport properties of the heterojunction were stud- ied by the LCR meter. The I-V curves suggest that rectification property of La1-xCaxMnO3/Siand La1-xSrxMn03/Siheterojunctions is similar to traditional semiconductor p-n junction. However La1-xSrxMn03/Si is obviously superior to La1-xCaxMnO3/La1-xSrxMnO3/Si probably due to its smaller crystal lattice mismatch with Si substrate and weaker ability to local carriers in films. In the double film heterojunction,La1-xCaxMnO3/La1-xSrxMnO3/Si has a good rectification characteristic because of its p ＋-p-n structure while La1-xCaxMnO3/La1-xSrxMnO3/Si heterojunction has a complicated electrical orooertv resulted from its n-p-n energy band structure.