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

DOI: 10.5185/amlett.2016.6364

Publication Date (Web): Aug 01, 2016

Copyright © IAAM-VBRI Press

E-mail: akhilesh.physics@gmail.com

Abstract

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 A_1g and E_2g with a separation of 26.5 cm^-1. Ultrathin MoS₂ layers, exfoliated from the sintered sample, showed the reduced separation between Raman peaks A_1g and E_2g of 24.5 cm^-1 few layer MoS₂.

Keywords

MoS₂, sintering, X-ray diffraction, Raman scattering.