One-Step CVD Growth and Interlayer Coupling Characteristics of Twisted MoS2/MoS2/MoS2 Homotrilayers

Two-dimensional (2D) bilayer transition-metal dichalcogenide (TMD) vertical homostructures with tunable twist angles in the range of 0-60 degrees have been intensively studied owing to the twist-angle-dependent novel optical properties, offering new opportunities for the design of optoelectronic devices. However, the trilayer TMD homostructures with two twisted interfaces can create more freedom to modulate the physical properties, and the direct chemical vapor deposition (CVD) growth of such unique structures has been rarely reported. Here, we present a single-step CVD strategy to grow 2D twisted MoS2/MoS2/MoS2 homostructures with two twisted interfaces. Experimentally, the effect of two twisted interfaces in the twisted MoS2 homotrilayers on the optical properties is revealed by the emergence of Moire phonon FA(1g) in the high-frequency Raman spectrum, evolution of two breathing modes in ultralow frequency Raman spectra, and the appearance of indirect band gap exciton in the temperature-dependent photoluminescence spectra. Our study may provide a novel pathway to modulate the performance of 2D MoS2 crystals, ensuring them promising applications in twistronics.