The role of substrate purity and its crystallographic orientation in the defect density of chemical vapor deposition grown monolayer graphene

RSC Advances ◽  
2015 ◽  
Vol 5 (85) ◽  
pp. 69110-69118 ◽  
Author(s):  
Munu Borah ◽  
Dilip K. Singh ◽  
Kiran M. Subhedar ◽  
Sanjay R. Dhakate

Here, we are reporting about the role of the copper substrate purity and its crystallographic orientation in the quality of the graphene grown using a low pressure chemical vapor deposition technique.

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2150
Author(s):  
Maryam A. Saeed ◽  
Ian A. Kinloch ◽  
Brian Derby

The chemical vapor deposition (CVD) of graphene on liquid substrates produces high quality graphene films due to the defect-free and atomically flat surfaces of the liquids. Through the detailed study of graphene growth on liquid Sn using atmospheric pressure CVD (APCVD), the quality of graphene has been found to have a close relationship with hydrogen flow rate that reflects on hydrogen partial pressure inside the reactor (PH2) and hydrogen solubility of the growth substrates. The role of PH2 was found to be crucial, with a low defect density monolayer graphene being obtained in low PH2 (90.4 mbar), while partial graphene coverage occurred at high PH2 (137.3 mbar). To further understand the role of substrate’s composition, binary alloy with compositions of 20, 30, 50, 60 and 80 wt.% tin in copper were made by arc-melting. Graphene quality was found to decrease with increasing the content of copper in the Cu–Sn alloys when grown using the conditions optimised for Sn substrates and this was related to the change in hydrogen solubility and the high catalytic activity of Cu compared to Sn. This shall provide a tool to help optimising CVD conditions for graphene growth based on the properties of the used catalytic substrate.


2016 ◽  
Vol 83 ◽  
pp. 573-580 ◽  
Author(s):  
Mohamad Saufi Rosmi ◽  
Sachin M. Shinde ◽  
Nor Dalila Abd Rahman ◽  
Amutha Thangaraja ◽  
Subash Sharma ◽  
...  

2010 ◽  
Vol 442 ◽  
pp. 195-201
Author(s):  
F. Iqbal ◽  
A. Ali ◽  
A. Mehmood ◽  
M. Yasin ◽  
A. Raja ◽  
...  

We report the growth of SiC layers on low cost p-type silicon (100 and/or 111) substrates maintained at constant temperature (1050 - 1350oC, ∆T=50oC) in a low pressure chemical vapor deposition reactor. Typical Fourier transform infrared spectrum showed a dominant peak at 800 cm-1 due to Si-C bond excitation. Large area x-ray diffraction spectra revealed single crystalline cubic structures of 3C-SiC(111) and 3C-SiC(200) on Si(111) and Si(100) substrates, respectively. Cross-sectional views exposed by scanning electron microscopy display upto 104 µm thick SiC layer. Energy dispersive spectroscopy of the layers demonstrated stiochiometric growth of SiC. Surface roughness and morphology of the films were also checked with the help of atomic force microscopy. Resistivity of the as-grown layers increases with increasing substrate temperature due to decrease of isolated intrinsic defects such as silicon and/or carbon vacanies having activation energy 0.59 ±0.02 eV.


2012 ◽  
Vol 1447 ◽  
Author(s):  
Siva P Adusumilli ◽  
Tara P Dhakal ◽  
Charles R Westgate

ABSTRACTPyrite phase of FeS2 has attracted substantial attention in the field of thin film solar technology because of its high optical absorption coefficient (~5 x 105 cm-1 at hν > 1.3eV) and the band gap of 0.95 eV. In this research, we have grown highly pure iron pyrite films using a low temperature atmospheric pressure chemical vapor deposition technique. The synthesis temperature is in the range of 375-400°C and Di-tert-butyl disulfide (TBDS) is used as the sulfur precursor. TBDS is a safe and low cost sulfur source unlike H2S, which is highly toxic and requires extreme care in handling. The films obtained were uniform and free from common impurity phases such as troilite and marcasite. The FeS2 films grown earlier with CVD synthesis and sulfurized using H2S had pinholes and contained secondary phases like marcasite and troilite. The FeS2 pyrite phase was confirmed using various characterization techniques that included SEM, EDS, XRD and XPS.


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