Low-temperature synthesis and growth model of thin Mo2C crystals on indium

Omer Refet Caylan,Goknur Cambaz Buke

doi:10.1038/s41598-021-87660-7

Omer Refet Caylan, Goknur Cambaz Buke

Open Access

https://doi.org/10.1038/s41598-021-87660-7

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Abstract

Chemical vapor deposition is a promising technique to produce Mo2C crystals with large area, controlled thickness, and reduced defect density. Typically, liquid Cu is used as a catalyst substrate; however, its high melting temperature (1085 °C) prompted research groups to search for alternatives. In this study, we report the synthesis of large-area thin Mo2C crystals at lower temperatures using liquid In, which is also advantageous with respect to the transfer process due to its facile etching. SEM, EDS, Raman spectroscopy, XPS, and XRD studies show that hexagonal Mo2C crystals, which are orthorhombic, grow along the [100] direction together with an amorphous carbon thin film on In. The growth mechanism is examined and discussed in detail, and a model is proposed. AFM studies agree well with the proposed model, showing that the vertical thickness of the Mo2C crystals decreases inversely with the thickness of In for a given reaction time.

Highlights

Chemical vapor deposition is a promising technique to produce Mo2C crystals with large area, controlled thickness, and reduced defect density
The reason is attributed to the increased viscosity of In-Cu alloy, which results in lower diffusion of Mo to the surface
We showed that In may be an ideal substrate for growing Mo2C crystals via chemical vapor deposition (CVD) because it enables the formation of high quality, large-area, thin M o2C crystals at lower temperatures (1000 °C) than copper (1085 °C); and its facile etching makes the transfer process easy

Summary

Introduction

Chemical vapor deposition is a promising technique to produce Mo2C crystals with large area, controlled thickness, and reduced defect density. We report the synthesis of large-area thin Mo2C crystals at lower temperatures using liquid In, which is advantageous with respect to the transfer process due to its facile etching. With the focus on Mo2C, chemical vapor deposition (CVD) synthesis proved to be a very promising approach for achieving large area, controlled thickness, and reduced defect density[6]. In this method, a Cu foil on top of the Mo substrate (Mo-Cu stack) is heated. Young et al.[18] studied the growth of thin Mo2C on In-Cu alloy and showed

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