Interface engineering of 2D van der Waals heterostructures for high-temperature optical communication

Two-dimensional (2D) semiconductor materials maintain high carrier mobility, exceptional physical properties, thermal stability, and highly tunable band structures, making them ideal for designing high-temperature field-effect transistors (FETs) and photodiodes. However, most atoms of these materials are located on the surface, making them susceptible to degradation due to oxidation and decomposition at high temperatures. Here, we employed hexagonal boron nitride (hBN) to encapsulate molybdenum disulfide (MoS₂), resulting in enhanced operation stability at temperatures above 523 K. Temperature-dependent photoluminescence (PL) measurements reveal that hBN encapsulation increases the activation energy (E_a ∼ 67 meV), indicating superior thermal stability. Additionally, the hBN-encapsulated tungsten diselenide (WSe₂)–MoS₂ p–n junction exhibits a thermally stable ideality factor of ∼1.149 at 558 K. By leveraging the stable photoresponse at high temperatures, we further successfully realized a light communication system with enhanced security and reliability. These findings can pave the way for the development of 2D FETs and photodiodes in extreme environments.