LaAlO_3/SrTiO_3界面增强光伏效应

探索LaAlO_3/SrTiO_3(LAO/STO)界面产生的新奇物理特性对理解关联电子系统中多自由度耦合和设计功能材料器件具有重要的价值.本文通过脉冲激光沉积方法在SrTiO_3基底上制备了LAO/STO薄膜,研究了正面照射LAO/STO膜面和侧面照射LAO/STO界面时的光伏效应,探讨了LAO/STO界面对光伏效应的影响.研究结果表明,在同样光照能量下侧面照射LAO/STO界面产生的光电压远高于正面照射LAO/STO膜面产生的光电压,说明LAO/STO界面对光伏效应有明显的增强作用.通过偏压调控可以进一步增强照射LAO/STO界面产生的光电压,当偏压为60 V时, LAO/STO样品的位置探测灵敏度达到了36.8 mV/mm.这些研究结果为设计场调控位置敏感探测器等新型光电子器件提供了新的思路.

Enhanced photovoltaic effect in LaAlO3/SrTiO3 interface

Since high-mobility electron gas,which is also called two-dimensional electron gas,was discovered at the LaAlO3/SrTiO3(LAO/STO)interface,SrTiO3-based heterostructures and nanostructures have become an attractive platform for novel nanoelectronic devices.Exploring the novel physical properties of LAO/STO interface and the mechanisms of interface effect is the key to designing and fabricating the new photoelectric devices.The LAO/STO sample is prepared on an STO(001)substrate by pulsed laser deposition.In order to study the influence of interface effect on photovoltaic effect in the LAO/STO sample,a KrF pulse laser with a wavelength of 248 nm and an energy density of 50 mJ/cm2 is chosen as an ultraviolet light source,a sampling oscilloscope of 350 MHz is used to measure the photovoltages,and a precision adjustable slit is adopted to control the size of irradiation area.The photovoltaic effect is studied under the condition of applied electric field at ambient temperature.The experimental results prove that the photovolatge of irradiating on the side of sample(LAO/STO interface)is higher than on the front of sample(film surface)under the same area of irradiation.Lateral photovoltaic effect is discovered in the LAO/STO sample.Irradiating on the side of sample(LAO/STO interface)can further improve the lateral photovoltaic effect in the LAO/STO sample.The opencircuit photovoltage depends linearly on the illuminated position,and the sensitivity reaches 36.8 mV/mm.The sensitivity of the lateral photovoltaic effect can be modified by the bias voltage.The experimental results not only contributes to better understanding the interface effect in LAO/STO interface,but also provides a basis for designing and using photoelectric devices for position-sensitive detection.