弯曲应变下单根GaAs纳米线的电学性能的原位透射电子显微镜研究

In situ study on transport property of bending GaAs nanowires in transmission electron microscope

在透射电子显微镜下,对单根GaAs纳米线实施了原位弯曲变形并获得了其弯曲变形下的电输运性能特性。本研究中,利用扫描透射探针系统和电子束诱导碳沉积技术,选取了单根GaAs纳米线并将纳米线两端与两根钨针尖连接固定。控制可移动的钨针尖,使GaAs纳米线发生弯曲变形同时获得相应的电流-电压曲线。有限元分析表明当纳米线的两端都固定时,纳米线同时承受了压缩应变和拉伸应变,其中压缩应变分布更为广泛。随着变形增加,GaAs纳米线的电导率增加了55%,这可能归因于弯曲变形下压缩与拉伸应变对GaAs纳米线能带结构的共同作用。

In a transmission electron microscope, in-situ deformation process and measurement of electrical transport properties were performed on individual GaAs nanowires. The single GaAs nanowire was selected and bonded between two tungsten pinpoints with assistance of piezo system and electron-beam induced deposition technique. By controlling the movable tungsten pinpoint, bending process of the bonded nanowire and the corresponding current-voltage curves were obtained simultaneously. Strain distributions analyzed using finite element analysis method indicate that the GaAa nanowire was mostly under compressive strain when it’ s both ends were restrained. The conductivity was only enhanced about 55% with increasing deformation which may be attributed to co-existence of tension and compression in the bended GaAs nanowires.