Bubble formation in van der Waals crystals: A platform for fundamental studies

van der Waals (vdW) crystals have attracted great interest for the exceptional electronic, optical, chemical, and mechanical properties they reveal in their two-dimensional (2D) form. Furthermore, they are extremely flexible, so that they can be subjected to high strains. Here, we show how micro-scale mechanical deformations in these materials represent an ideal platform to study their fundamental properties. More specifically, we exploit the capability of hydrogen-ion irradiation to induce the formation of 1-layer-thick micro-bubbles, and we also show that their formation can be spatially controlled by litographic approches. These bubbles both modify the opto-electronical properties of the crystal and represent a unique system to study its mechano-elastic and adhesive properties.