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

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.

Low Temperature Synthesis and Growth Model of Thin Mo2C Crystals on Indium

CVD method 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 a research for alternatives. In this study, we report the synthesis of large-area thin Mo2C crystals on liquid In surface at 1000 C for the first time. SEM, EDS, Raman Spectroscopy, XPS and XRD studies show that the hexagonal shaped Mo2C crystals, that are orthorhombic, grow along the [100] direction together with amorphous carbon thin film on In. The growth mechanism is examined and discussed in detail and a model is proposed. The AFM studies agree well with the proposed model showing that the vertical thicknesses of the Mo2C crystals decrease inversely with the thickness of the In for the given reaction time.

Structural Analysis and Electrical Properties of Amorphous Carbon Thin Films

The amorphous carbon (a-C) thin films have been developed by many researchers due to many superior properties. The aim of this research to study the structure of amorphous carbon thin film. Amorphous carbon was successfully prepared by carbonization of up to 200°C. Organic compounds that used in this research were coconut sap and its derivatives. The variation used in this research was a calcinating temperature ranging from 250°C, 400°C, and 600°C. Amorphous carbon powder was then mixed with aquades. Exfoliation process has been applied using an ultrasonic cleaner for 2 hours and then centrifuged at 4000 rpm for 30 minutes. Deposition technique used in this research was spin - coating. The X-ray diffraction pattern shows that the carbonization process produces amorphous carbon phase at diffraction angle of 2θ =15-30°. The infrared absorbtion in the region 500 to 4000 cm-1 was resolved into several peaks, which were assigned to C ̶ H, C ̶ O, C ̶ C, C=C and O ̶ H bonding. Photo Emission Spectroscopy (PES) was used to measure the percentage of sp2 and sp3 configuration in the sample. From the PES data, the percentage of sp2 configuration of coconut sap heated at 400°C is 55.32%. Four-point probe method was also used to measure the conductivity and band gap of each material, resulting in 2.67 – 8.33 S/m and 0.15 – 0.49 eV respectively.