Thermomechanical modeling of bubble migration under local laser heating in van der Waals heterostructures

초록

Trapped interfacial bubbles in van der Waals (vdW) heterostructures degrade electronic performance but also present opportunities for local strain engineering. We develop a comprehensive thermomechanical model to investigate how localized continuous-wave (CW) laser heating can be used to manipulate such bubbles in hBN/graphene/hBN stacks. By integrating f inite-difference heat conduction simulations with analytical models of bubble energetics, we quantify laser-induced temperature distributions and the conditions required for bubble migration. Our model incorporates optical absorption in both the encapsulated 2D layers and silicon substrate, vertical and lateral heat spreading, and interfacial thermal resistance. A temperature-based criterion for bubble migration is derived from the energy balance between internal pressure buildup and adhesion-limited motion. We show that focused laser power (40 mW) can raise local temperatures to 800 K, sufficient to overcome adhesion barriers for bubbles above a critical size. Notably, our analysis reveals that while the migration direction depends on a competition between internal pressure and adhesion energy gradients, the temperature dependence of adhesion typically dominates, driving bubbles toward colder regions under realistic conditions. These results offer a predictive framework for optothermal interface engineering, enabling spatially controlled bubble removal, cleanliness enhancement, and programmable strain in 2D material devices.

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