Nanoscale Topological Morphology Transition and Controllable Thermal Conductivity of Wrinkled Hexagonal Boron Nitride: Implications for Thermal Manipulation and Management

Understanding the nanoscale morphology and transition process of two-dimensional (2D) materials would promote the design of emerging 2D devices with controllable properties. Wrinkles induced by mechanical strains have attracted extensive interest as a promising approach to the predictable modulation of structures. Here, a reciprocal-space characterization is implemented to capture the nanoscale topological morphology of free-standing monolayer hexagonal boron nitride (h-BN). Various morphology types and transition processes under different strains are observed. For biaxial compressive strain, the topological morphology of wrinkled h-BN is found to be the same as that of pristine h-BN. For uniaxial compressive strain, different from commonly supposed one-step transition, a three-step morphology transition process within a very narrow strain range is uncovered. The topological morphology under shear strain and angular pinching strain is investigated as well. In addition, the manipulation of thermal conductivity of h-BN by wrinkles is demonstrated to exemplify wrinkle-based thermal manipulation and thermal management in electronic devices.