Thermal modulation of crystallinity and defect landscape in sputtered MoS2 thin films for optoelectronic applications

This study investigates the influence of substrate temperature on the structural, optical, and electrical properties of MoS 2 thin films deposited via radio-frequency (RF) magnetron sputtering. Films were grown at four substrate temperatures: room temperature (RT), 100 °C, 200 °C, and 300 °C. X-ray diffraction (XRD) and Raman spectroscopy revealed that increasing temperature enhanced crystallinity, reduced microstrain, and narrowed vibrational mode peaks, indicating thermally induced grain coarsening and reduced structural disorder. Field emission scanning electron microscopy (FESEM) showed a progression from irregular grains to more uniform and compact morphologies with elevated temperatures. Photoluminescence (PL) analysis identified both direct (∼1.83 eV) and indirect (∼1.63 eV) transitions, supporting the presence of multilayered domains and revealing enhanced optical quality at 200 °C. Electrical measurements indicated a trade-off between mobility and carrier concentration, with peak hole mobility (3.81 cm 2 /V·s) observed at 300 °C. These findings demonstrate that a sputtering temperature of 200 °C offers an optimal balance between crystallinity, electrical transport, and low structural disorder, making it ideal for integrating MoS 2 thin films into high-performance optoelectronic devices. • In-situ thermal control during RF magnetron sputtering tailors crystallinity and reduces defects in MoS 2 films. • Optimal growth at 200 °C produces well-aligned grains with minimal sulfur vacancies. • Enhanced electrical and optical performance demonstrated through mobility and optoelectronic measurements. • Low-temperature, scalable fabrication route for high-quality TMD thin films ready for device integration.