Low-noise platform for in situ structural and electrical characterization by sub-Ångstrøm low-voltage transmission electron microscopy (SALVE IV)

该项目旨在开发一个低噪声平台，用于使用低压透射电子显微镜在亚-Ångstrøm分辨率下研究光束敏感样品，从而实现同时成像和施加于样品的电偏置的原位变化。通过聚焦离子束（FIB）技术，将在氮化硅膜上切割亚微米大小的狭缝，然后用单层石墨烯片覆盖，产生弱散射，完美的晶体样品支撑，其信号可以通过傅里叶滤波从TEM图像中去除。通过光刻技术将金属微触点添加到平台上，并用FIB沉积的纳米线桥接样品的剩余间隙，从而使电流在TEM中观察时通过样品成为可能。这种能力将被用于研究(i)晶格缺陷和/或吸附物对石墨烯电导率的影响，以及（ii） GaN和AlN等超薄半导体层的结构和电性能。

This project is intended to develop a low-noise platform for investigating beam-sensitive samples at sub-Ångstrøm resolution using low-voltage transmission electron microscopy, enabling simultaneous imaging and in situ variation of the electrical bias applied to the specimen. By means of the focused ion-beam (FIB) technique, submicrometer-sized slits will be cut in silicon nitride membranes and then covered by single-layer sheets of graphene, yielding a weakly scattering, perfectly crystalline sample support whose signal can be removed from the TEM image by Fourier filtering. Metallic microcontacts will be added to the platform by lithography, and the remaining gap to the sample will be bridged by nanowires deposited by FIB, thereby making it possible to pass electrical current through a specimen during observation in the TEM. This capability will be exploited to study (i) the influence of lattice defects and/or adsorbates on the electrical conductivity of graphene and (ii) the structure and electrical properties of ultrathin layers of semiconductors like GaN and AlN.