Aligned monolayer MoS2 ribbons growth on sapphire substrate via NaOH-assisted chemical vapor deposition

Abstract

This study reports the growth of aligned monolayer molybdenum disulfide (MoS2) ribbons on a sapphire substrate via NaOH-assisted chemical vapor deposition. The length of MoS2 ribbon is up to 400 μm. The MoS2 ribbon has excellent single crystal properties, a carrier mobility of {150 cm2 V−1 s−1, and a optical response of 103 mA W−1 at a wavelength of 550 nm. The growth model of MoS2 ribbons was given. NaOH reacts with MoO3 to form sodium molybdate droplets, which increase the fluidity of the molybdenum source on the substrate, realizing the vapor–liquid–solid growth of MoS2 on sapphire. The monolayer MoS2 ribbons have two kinds of arrangements on the sapphire substrate, one is the oriented growth affected by the interlayer van der Waals force and the lattice, and the other is the aligned growth constrained by the sapphire step. Our results promote the basic research and device applications of MoS2, and introduce a new way of synthesizing other one dimensional (1D) and 2D nanostructures.