Immobilized Precursor Particle Driven Growth of Centimeter-Sized MoTe₂ Monolayer

Abstract

Molybdenum ditelluride (MoTe 2 ) has attracted evergrowing attention in recent years due to its novel characteristics in spintronics and phase-engineering, and an efficient and convenient method to achieve large-area high-quality film is an essential step toward electronic applications. However, the growth of large-area monolayer MoTe 2 is challenging. Here, for the first time, we achieve the growth of a centimetersized monoclinic MoTe 2 monolayer and manifest the mechanism of immobilized precursor particle driven growth. Microscopic characterizations reveal an obvious trend of immobilized precursor particles being consumed by the monolayer and continuing to provide a source for the growth of the monolayer. Time-of-flight secondary ion mass spectrometry verifies the attachment of hydroxide ions on the surface of the MoTe 2 monolayer, thereby realizing the inhibition of crystal growth along the [001] zone axis and the continuous growth of the MoTe 2 monolayer. The first-principles DFT calculations prove the mechanism of immobilized precursor particles and the absorption of hydroxide ions on the MoTe 2 monolayer. The as-grown MoTe 2 monolayer exhibits a surface roughness of 0.19 nm and average conductivity of 1.5 × 10 −5 S/m, which prove the smoothness and uniformity of the MoTe 2 monolayer. Temperature-dependent electrical measurements together with the transfer characteristic curves further demonstrate the typical semimetallic properties of monoclinic MoTe 2 . Our research elaborates the microscopic process of immobilized precursor particles to grow large-area MoTe 2 monolayer and provides a new thinking about the growth of many other two-dimensional materials.

Structural Evolution of Atomically Thin 1T’‐MoTe2 Alloyed in Chalcogen Atmosphere

“…The XPS spectrum of Te 3 d 5/2 and Te 3 d 3/2 corresponding to the aged specimen displays prominent signals situated at 576.2 and 586.5 eV, respectively, which correspond to Te–O bonds, manifesting the incorporation of element O in 1T’‐MoTe 2 (Figure 8g). [ 13 ] The presence of weak oxidized Te–O bands in the as‐grown sample is due to an unavoidable short exposure time to air before and during the measurement. Characteristic Raman vibrational modes for 1T’‐MoTe 2 are largely diminished for unprotected samples after exposure in air for 1 h (red curve in Figure 8h).…”

“…[2][3][4] Recently, tremendous efforts have been devoted to preparing 2D transition metal dichalcogenide (TMD) alloys, which adopt atomic thickness, diverse electronic structures, and show great potential in nanoelectronics, flexible devices, and energyharvesting applications. [5][6][7][8][9][10][11][12][13][14] Janus TMD monolayer alloys having different chalcogen atoms situating at the top and bottom atomic planes separately break the out-of-plane mirror symmetry, thus generating vertical dipoles and enabling spin manipulation. [15,16] High-entropy 2D TMD alloys combining multiple metal components in near-equiatomic concentrations exhibit outstanding electrochemical performance.…”

Dual‐Regulation of Defect Sites and Vertical Conduction by Spiral Domain for Electrocatalytic Hydrogen Evolution

“…The height of pyramid is approximately 30 nm, and the step height at the center measures 0.7 nm, which agrees well with the thickness of a single layer of MoTe 2 . [14] Raman spectra of the spiral MoTe 2 show no apparent frequency shift but gradually decreased intensity for E 2g mode at 232 cm À 1 from edge base to central top as marked in the inset optical image (Figure 1d), whose Raman mapping is presented in Figure S4. However, the A 1g mode (170 cm À 1 ) and B 2g mode (289 cm À 1 ) merely appear in the few-layer area.…”

Low-temperature growth of ultrathin and epitaxial Mo2C nanosheets via a vapor–liquid–solid process

“…In addition, the minimum thickness of Mo 2 C nanosheets is about 12 nm. As Zou et al 43,44 reported, we consider that introducing hydroxide groups (-OH) into the precursor solution is an effective method to further reduce the thickness of ultrathin Mo 2 C.…”