CVD synthesis and characterization of thin Mo2C crystals. Issue 10 (29th June 2020)

• Record Type: Journal Article
• Authors: Turker, Furkan; Caylan, Omer R.; Mehmood, Naveed; Kasirga, Talip S.; Sevik, Cem; Cambaz Buke, Goknur
• Is Part Of: Journal of the American Ceramic Society. Volume 103:Issue 10(2020)
• Page Start: 5586
• Page End: 5593
• Publication Date: 2020-06-29
• Subjects: 2D Mo2C -- copper foil -- CVD -- graphene -- impurities; Ceramics -- Periodicals; 620.1405
• DOI: 10.1111/jace.17317
• Languages: English
• ISSNs: 0002-7820

Abstract

Abstract: In this study, we present an investigation on the growth of thin Mo2 C crystals via chemical vapor deposition using CH4 . Optical microscopy (OM), scanning electron microscopy (SEM), atomic force microscopy(AFM), and Raman spectroscopy studies show that the morphology and the thickness of Mo2 C crystals are strongly affected by the impurities in the system, the thickness of the copper substrate, and the graphene presence on Cu surface prior to Mo2 C formation. Our studies show that during the CVD process, orthorhombic Mo2 C crystals grow along the [100] direction on two different regions: directly on Cu surface or on graphene covered regions. Mo2 C crystals that form on graphene are found to be thinner and less defective compared to the ones formed on the Cu surface. This is attributed to graphene acting as an additional diffusion barrier for Mo atoms diffusing through the copper. In addition to the graphene beneath the Mo2 C crystal, Raman studies indicate that graphene may grow also on top of the Mo2 C crystal, forming a graphene/Mo2 C/graphene sandwich structure which may offer interesting properties for electronic applications. Abstract : In this report, chemical vapor deposition (CVD) studies on Mo2 C crystals show that the impurities in the system affect the growth mechanism and final morphology of the crystals. Moreover, on the contrary to the published reports on α‐Mo2 C growth on Cu via CVD, our studies demonstrate that thin α‐Mo2 C crystals grow either on Cu surface or on simultaneously formed graphene. The crystals grown on graphene show more intact and thinner morphology than the ones formed on bare Cu. In addition, Raman studies indicate that graphene grows only on the Mo2 C crystals which are on top of graphene, rather than the islands formed on bare Cu, forming graphene/Mo2 C/graphene sandwich structure which may offer exotic optoelectronic properties.