Final Report Summary - NEMINTEM (In-situ NanoElectrical Measurements in a Transmission Electron Microscope)
Nanocharacterization by High-Resolution Transmission Electron Microscopy (HRTEM) is becoming increasingly important. It allows to determine local atomic arrangements, element compositions as well as electronic structures. In the ERC project NanoElectrical Measurements in a Transmission Electron Microscope (NEMinTEM) we have developed the possibility to perform in-situ HRTEM in combination with electrical measurements on nanostructures. This combination allows one to see what one is measuring, and in case of electron beam modifications measure what one is changing. We have developed the equipment and the methodology to perform nano-electrical measurements of nanostructures in-situ in a HRTEM. This allowed us to image, measure and change devices in-situ, and we have shown this on nanowires, graphene and metallic nanowires. We have used the equipment and methodologies developed in the project and we have realized several new equipment, based on the specific needs of the NEMinTEM experiments that we wanted to perform. An example of the latter is the realization of a holder with which we can heat a specimen and modify it, do electrical measurements and expose in-side the TEM the made structure to a gas. An application of the latter equipment is the electrical characterization of graphene nanoribbons in chosen gas atmospheres with subsequent imaging after the gas is pumped out. We have done the planned NEMinTEM experiments on semiconductor nanowires, metallic and oxide nanobridges and graphene nanoribbons. In all cases we encountered phenomena that could not be fully explained by the existing theory. Examples of these are the locations where metal atoms are removed in and around metallic nanobridges during electromigration and the material displacements and its composition in semiconductor nanowires while passing a large current through it. Furthermore we have performed NEMinTEM experiments on Li-based batteries, and we are investigating whether the electrical double layer at metal-liquid interfaces can be imaged with electron holography. In the last part of the project we used a fast direct electron camera, for the experiments where the changes occur fast and frame rates of 50-200 frames per second are needed. It is to be expected that once NEMinTEM is mature, it will be applied to many more materials and by many research groups.