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

该项目旨在开发一种低噪声平台，用于使用低电压透射电子显微镜在亚纳斯特罗姆分辨率下研究束敏感样品，从而能够同时成像和原位变化施加到样品上的电偏置。利用聚焦离子束(FIB)技术，在氮化硅薄膜上切割亚微米级的狭缝，然后用单层石墨烯覆盖，产生弱散射、完美结晶的样品载体，其信号可以通过傅立叶滤波从透射电子显微镜图像中去除。金属微触点将通过光刻技术添加到平台上，剩余的间隙将通过FIB沉积的纳米线连接到样品上，从而使在透射电子显微镜观察过程中电流通过样品成为可能。这一能力将被用来研究(I)晶格缺陷和/或吸附对石墨烯导电性的影响，以及(Ii)GaN和AlN等超薄半导体的结构和电学性质。

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.