Fabrication of damage-free and/or contamination-free sub-um electrodes using PMMA masks

Quality of the electrical contacts and interfaces in various metal/semiconductor/insulator heterostructures is one of the pivotal aspects in both applied and fundamental research areas. For instance, non-optimal contact resistance can limit the overall efficiency of a certain developed technology and thus considerably narrow the range or fully block its practical application. On the other hand in fundamental research it is often the case that the manifestation of targeted phenomenon crucially depends on the level of contamination in the fabricated experimental samples. Here we offer a set of recipes that are aimed at contamination-free and damage-free fabrication of the devices, mostly developed for the two dimensional materials, but nevertheless applicable for a wider range of the systems, where the quality of the interfaces and/or non-invasiveness of the fabrication recipes are important. Our recipes are based on the preparation of the flexible PMMA membranes, with the help of which we can prepare residue-free or damage-free electrical connections to the studied material.