Interface carrier transport in van der Waals heterostructures: roles of bubbles, annealing, and electric field screening.

van der Waals (vdW) two-dimensional (2D) materials are pivotal for advancing high-performance electronic and optoelectronic devices in the post-Moore era. However, their practical performance is severely limited by interface quality, which poses a critical bottleneck. Herein, we systematically investigate the electrical response of vdW interfaces under electric fields, thermal annealing, and alternating current excitation, thereby establishing a theoretical basis and technical pathway for interface optimization. Specifically, using peak force tunneling amperemeter (TUNA) atomic force microscopy (AFM), we directly observe that interface bubbles impede interlayer carrier transport in vdW heterostructures. Furthermore, thermal annealing investigations reveal a non-monotonic modulation of the rectifying behavior in the heterostructure. Additionally, electric field distribution simulations provide insights into the mechanisms for the attenuation or screening of vertical electric fields across various vdW interfaces. Overall, this work offers a rigorous, actionable framework integrating physical insights and application needs, with significant implications for precise interface design, optimized thermoelectric processing windows, and reliable integration of wafer-scale 2D material devices.