缺氧La_(0.6)Ca_(0.4)MnO_(3-δ)薄膜的光响应特性  

Optical Response in Oxygen-Deficient La_(0.6)Ca_(0.4)MnO_(3-δ) Thin Films

作　　者：严资杰[1] 袁孝[1] 高国棉[2] 金克新[2] 陈长乐[2] 

机构地区：[1]华中科技大学光电子科学与工程学院,武汉430074 [2]西北工业大学理学院,西安710072

出　　处：《光学学报》2007年第10期1901-1904,共4页Acta Optica Sinica

基　　金：国家自然科学基金(60171034;10476010和10676010)资助的课题

摘　　要：采用波长均为532 nm的连续激光和脉冲激光研究了缺氧La0.6Ca0.4MnO3-δ(LCMO)薄膜的光响应特性。分析了在金属态和绝缘态时,缺氧对LCMO薄膜光响应的不同影响。在脉冲宽度7 ns、峰值功率750 mW的脉冲激光作用下,缺氧LCMO薄膜在室温下呈现出明显的光响应信号,其光电导增大36.4%,上升时间约30 ns。由于光子能量大于LCMO的禁带宽度,光子注入在薄膜中产生了电子-空穴对,而电子很容易被氧空位俘获,从而在薄膜中产生大量额外的空穴载流子,大量的空穴载流子可能诱发局域绝缘-金属相变,从而在薄膜中产生明显的光电导效应。实验显示出缺氧钙钛矿薄膜在光电器件上的巨大应用潜力。The optical response of oxygen-deficient La0.6Ca0.4MnO3-δ （LCMO） thin films was studied using continuous wave and pulsed lasers with wavelength of 532 nm. The influence of oxygen deficiency on the optical response of LCMO thin films in metallic and insulating state has been analyzed. At room temperature, oxygendeficient LCMO thin films show obvious optical response with photo-conductivity improved by 36.4 % and rise time of 30 ns when illuminated by a laser pulse of 7 ns duration at the light power of 750 mW. Since the laser photon energy is larger than the band gap of the thin films, electron-hole pairs are created in the film. For the electrons can be captured by the oxygen vacancy easily, then extra holes carriers are produced, which can induce local insulator-metal phase change and obvious optoelectronic effect. The results show potential application of oxygen-deficient LCMO thin films in optoelectronic devices.

关 键 词：薄膜 钙钛矿薄膜 光响应 氧缺陷 庞磁电阻 

分 类 号：O484.41[理学—固体物理]