Structural and optical properties of bulk MoS2 for 2D layer growth
1Solid State Physics Laboratory, DRDO, Lucknow Road, Timarpur, Delhi 110054, India
2Indian Institute of Science, Bengaluru, Karnataka 560012, India
Adv. Mater. Lett., 2016, 7 (10), pp 777-782
Publication Date (Web): Aug 01, 2016
Copyright © IAAM-VBRI Press
Molybdenum-di-sulfide (MoS2) is being considered as an alternative 2-D material to graphene. Deposition of ultrathin MoS2 layer from bulk MoS2 sample is an important criterion in determining the viability of its application. This paper discusses about growth and characterization of bulk MoS2 pellet from MoS2 powder and exfoliation of MoS2 layer from it. The MoS2 pellets were sintered at different temperatures (500 - 850 ° in nitrogen atmosphere. The sintered samples were found to be polycrystalline in nature with hexagonal flakes of 100 nm – 1.0 µm sizes. In addition to MoS2 phase, surface of the bulk samples also has also some MoO3 phase content, which was found to decrease with the increase in sintering temperature, confirmed by XRD. The optical absorption study showed MoS2 absorptions around 1.82 eV, 2.01 eV due to spin orbit and direct band to band absorption from ?k-k valley. The sintered MoS2 samples were found to have characteristic Raman peaks of A1g and E2g with a separation of 26.5 cm-1. Ultrathin MoS2 layers, exfoliated from the sintered sample, showed the reduced separation between Raman peaks A1g and E2g of 24.5 cm-1 few layer MoS2.
MoS2, sintering, X-ray diffraction, Raman scattering.