Structural properties of MoS₂ layers grown by CVD technique

Abstract

Different layers of Transition Metal Dichalcogenide (TMDC) based compound MoS₂ have been grown on SiO₂/Si substrate by using the CVD technique. Raman spectra analysis of the samples showed that monolayer, bilayer and few layers of MoS₂ are grown when the duration of growth is varied. From the photoluminescence studies direct band gap of the samples are determined - band gap of the monolayer is highest and with the increase of number of layers there is a decrease in the value of the bandgap. The observed change in the band structure of MoS₂ with layer thickness is explained due to the quantum confinement effect. Microstructural studies are done using Scanning Electron Microscopy, distribution of triangular shape grains over the surface of the film is observed. Density, thickness and population of these grains are changed when the duration of growth is changed.

Keywords:

• Semiconductor
• Raman spectroscopy
• luminescence
• CVD

Acknowledgments

The authors are thankful to the Director, Solid State Physics Laboratory for his constant support in this research work and Mr. Anand for recording and analysis of Scanning Electron Micrographs.