Diverse Atomically Sharp Interfaces and Linear Dichroism of 1T' ReS2-ReSe2 Lateral p-n Heterojunctions

Creating heterojunctions between different 2D transition-metal dichalcogenides (TMDs) would enable on-demand tuning of electronic and optoelectronic properties in this new class of materials. However, the studies to date are mainly focused on hexagonal (2H) structure TMD-based heterojunctions, and little attention is paid on the distorted octahedral (1T') structure TMD-based heterojunctions. This study reports the large-scale synthesis of monolayer 1T' ReS2-ReSe2 lateral heterojunction with domain size up to 100 mu m by using two-step epitaxial growth. Atomic-resolution scanning transmission electron microscopy reveals high crystal quality of the heterojunction with atomically sharp interfaces. Interestingly, three types of epitaxial growth modes accompanying formation of three different interface structures are revealed in the growth of 1T' heterojunction, where the angle between the b-axis of ReS2 and ReSe2 is 0 degrees, 120 degrees, and 180 degrees, respectively. The 0 degrees and 180 degrees interface structures are both found to be more abundant than the 120 degrees interface structure owing to their relative lower formation energy. Electrical transport demonstrates that the as-grown heterostructure forms lateral p-n junction with intrinsic rectification characteristics and exhibits polarization-dependent photodiode properties. This is the first time the linear dichroism is achieved in 2D lateral heterostructure, which is important for the development of new devices with multi-functionality.