Work

Engineering the Morphology and Properties of MoS2 Films Through Gaseous Precursor-Induced Vacancy Defect Control

Year: 2025

Type: article

Abstract: The morphology, structure, and composition of CVD-grown molybdenum disulfide (MoS2) films were investigated under varying precursor vapor pressures. Increasing sulfur vapor pressure transformed the film morphology from well-defined triangular domains to structures dominated by sulfur-terminated zigzag edges. These morphological changes were accompanied by notable variations in both structural and electrical properties. Non-uniform precursor vapor distribution promoted the formation of intrinsic point defects. To elucidate this behavior, a thermodynamic model was developed to link growth parameters to native defect formation. The analysis considered molybdenum and sulfur vacancies in both neutral and charged states, with equilibrium concentrations determined from the corresponding defect formation reactions. Sulfur vapor pressure emerged as the dominant factor controlling defect concentrations. The model validated experimental observations, with films grown under optimum and sulfur-rich conditions, yielding a carrier concentration of 9.6×1011 cm-2 and 7.5×1011 cm-2, respectively. The major difference in the field-effect transistor (FET) performance of devices fabricated under these two conditions was the degradation of the field-effect mobility and the current switching ratio. The degradation observed is attributed to increased carrier scattering at charged vacancy defect sites.

Source: Nanomaterials

DOI: 10.3390/nano15221723

Authors: James Abraham, Nigel D. Shepherd, Chris Littler, A. J. Syllaios, Usha Philipose

Institution: University of North Texas

Language: English

Topic: 2D Materials and Applications

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,896

Funder: Office of Naval Research